Pediatric ambulatory pertussis epidemiology in France, recent updates

OBJECTIVES

Following various changes in the vaccine strategy in 2013 and the mandatory vaccination in 2018, we aimed to analyze the vaccination status, age, and source of contamination of pertussis and parapertussis cases in outpatient surveillance.

PATIENTS AND METHODS

Confirmed pertussis and parapertussis cases were enrolled by 35 pediatricians.

RESULTS

From 2014 to 2022, 73 confirmed cases of pertussis (n = 65) and parapertussis (n = 8) were reported. For children below 6 years of age, the number of cases with a 2 + 1 schedule (n = 22) was higher than that of those with a 3 + 1 schedule (n = 7). The age of cases with a 3 + 1 or a 2 + 1 schedule was not significantly different (3.8y ± 1.4 vs 4.2y ± 1.5). The main source of contamination was either adults or adolescents.

CONCLUSION

Vaccination status and source of contamination are crucial to study the impact of vaccination recommendations.

Association between the COVID-19 pandemic and pertussis derived from multiple nationwide data sources, France, 2013 to 2020

BackgroundInterventions to mitigate the COVID-19 pandemic may impact other respiratory diseases.AimsWe aimed to study the course of pertussis in France over an 8-year period including the beginning of the COVID-19 pandemic and its association with COVID-19 mitigation strategies, using multiple nationwide data sources and regression models.MethodsWe analysed the number of French pertussis cases between 2013 and 2020, using PCR test results from nationwide outpatient laboratories (Source 1) and a network of the paediatric wards from 41 hospitals (Source 2). We also used reports of a national primary care paediatric network (Source 3). We conducted a quasi-experimental interrupted time series analysis, relying on negative binomial regression models. The models accounted for seasonality, long-term cycles and secular trend, and included a binary variable for the first national lockdown (start 16 March 2020).ResultsWe identified 19,039 pertussis cases from these data sources. Pertussis cases decreased significantly following the implementation of mitigation measures, with adjusted incidence rate ratios of 0.10 (95% CI: 0.04-0.26) and 0.22 (95% CI: 0.07-0.66) for Source 1 and Source 2, respectively. The association was confirmed in Source 3 with a median of, respectively, one (IQR: 0-2) and 0 cases (IQR: 0-0) per month before and after lockdown (p = 0.0048).ConclusionsThe strong reduction in outpatient and hospitalised pertussis cases suggests an impact of COVID-19 mitigation measures on pertussis epidemiology. Pertussis vaccination recommendations should be followed carefully, and disease monitoring should be continued to detect any resurgence after relaxation of mitigation measures.

Pertussis surveillance results from a French general practitioner network, France, 2017 to 2020

Introduction

In France, three complementary surveillance networks involving hospitals and paediatrician practices currently allow pertussis surveillance among infants (<1 year old) and children (1–12 years old). Data on incidences among adolescents (13–17 years old) and adults (≥ 18 years) are scarce. In 2017, a sentinel surveillance system called Sentinelles network, was implemented among general practitioners (GPs).

Aim

The purpose of Sentinelles network is to assess pertussis incidence, monitor the cases’ age distribution and evaluate the impact of the country’s vaccination policy. We present the results from the first 4 years of this surveillance.

Methods

GPs of the French Sentinelles network reported weekly numbers of epidemiologically or laboratory-confirmed cases and their characteristics.

Results

A total of 132 cases were reported over 2017–2020. Estimated national incidence rates per 100,000 inhabitants were 17 (95% confidence interval (CI): 12–22) in 2017, 10 (95% CI: 6–14) in 2018, 15 (95% CI: 10–20) in 2019 and three (95% CI: 1–5) in 2020. The incidence rate was significantly lower in 2020 than in 2017–2019. Women were significantly more affected than men (83/132; 63% of women, p = 0.004); 66% (87/132) of cases were aged 15 years or over (median age: 31.5 years; range: 2 months–87 years). Among 37 vaccinated cases with data, 33 had received the recommended number of doses for their age.

Conclusions

These results concur with incidences reported in other European countries, and with studies showing that the incidences of several respiratory diseases decreased in 2020 during the COVID-19 pandemic. The results also suggest a shift of morbidity towards older age groups, and a rapid waning of immunity after vaccination, justifying to continue this surveillance.

Can vaccines control bacterial virulence and pathogenicity? Bordetella pertussis: the advantage of fitness over virulence

Some vaccines, such as diphtheria toxoid and acellular pertussis vaccines (aPVs), may favor the emergence of less pathogenic strains of the respective bacteria they target. This review discusses the impact of the wide use of aPV on Bordetella pertussis phenotype evolutions and their beneficial consequences in the light of the diphtheria toxoid immunization program experience and structuring evidence review in a causal analysis following Bradford Hill’s causality criteria. All aPVs contain the pertussis toxin (PT), the main virulence factor of B.pertussis, alone or with one adhesin (filamentous hemagglutinin (FHA)), two adhesins (FHA and pertactin (PRN)) or four adhesins (FHA, PRN and two fimbriae (Fim 2/3)). In countries where the coverage of aPVs containing PRN is high, PRN negative B.pertussis isolates are increasing in prevalence, but isolates nonproducing the other antigens are rarely reported. We hypothesize that the selective pressure at play with PRN should exist against all aVP antigens, although detection biases may hinder its detection for other antigens, especially PT. PT being responsible for clinically frank cases of the disease, the opportunity to collect PT negative isolates is far lower than to collect PRN negative isolates which have a limited clinical impact. The replacement of the current B.pertussis by far less pathogenic isolates no longer producing the factors contained in aPVs should be expected as a consequence of the wide aPV use.

Cocooning strategy: Pertussis vaccination coverage rate of parents with a new-born in 2016 and 2017 in France

BACKGROUND

The "cocooning" strategy was introduced in 2004 to protect infants too young to be vaccinated against pertussis, by immunizing their parents and close relatives. The study objective was to assess its implementation 12 years after its introduction by estimating the pertussis vaccination coverage rates (VCR) among parents of newborns.

MATERIALS AND METHODS

Pertussis VCR were estimated among all women who gave birth and men who took paternity leave, in 2016 or 2017, from a 1/97th random sample of French claims data. Two distinct study periods were defined based on current recommendations for the cocooning strategy: the "common practice" and the "parental project" periods.

RESULTS

In 2016, the pertussis VCR of women having given birth and men having taken paternity leave was 47.2 and 47.1%, respectively (46.1 and 45.6% in 2017, respectively). About one quarter of vaccinations were performed during the "parental project" period, with the vaccine most frequently reimbursed during the month of childbirth for women (57.1% in 2016 and 49.4% in 2017) and before or during the month the paternity leave began for men (about 78% in both 2016 and 2017). General practitioners were the main prescribers in private practice, even during the "parental project" period.

CONCLUSION

To optimize the protection for infants, the main objective of the cocooning strategy, pertussis immunization coverage of adults and seniors needs to be improved. Moreover, cocooning vaccination linked to a parental project needs to be performed earlier, during pregnancy (for those around the mother) or in immediate post-partum (e.g., during the maternity stay).

Hospital-based prospective study of pertussis in infants and close contacts in Tehran, Iran

Background

Pertussis remain a global health concern, especially in infants too young to initiate their vaccination. Effective vaccination and high coverage limit the circulation of the pathogen, yet duration of protection is limited and boosters are recommended during a lifetime. In Iran, boosters are given at 18 months and 6 years old using whole pertussis vaccines for which efficacy is not known, and pertussis surveillance is scant with only sporadic biological diagnosis. Burden of pertussis is not well understood and local data are needed.

Methods

Hospital-based prospective study implementing molecular laboratory testing in infants aged ≤6 months and presenting ≥5 days of cough associated to one pertussis-like symptom in Tehran. Household and non-household contact cases of positive infants were evaluated by comprehensive pertussis diagnosis (molecular testing and serology) regardless of clinical signs. Clinical evaluation and source of infection were described.

Results

A total of 247 infants and 130 contact cases were enrolled. Pertussis diagnosis result was obtained for 199 infants and 104 contact cases. Infant population was mostly < 3 months old (79.9%; 157/199) and unvaccinated (62.3%; 124/199), 20.1% (40/199) of them were confirmed having B. pertussis infection. Greater cough duration and lymphocyte counts were the only symptoms associated to positivity. Half of the contact cases (51.0%; 53/104) had a B. pertussis infection, median age was 31 years old. A proportion of 28.3% (15/53) positive contacts did not report any symptom. However, 67.9% (36/53) and 3.8% (2/53) of them reported cough at inclusion or during the study, including 20.8% (11/53) who started coughing ≥7 days before infant cough onset. Overall, only five samples were successfully cultured.

Conclusion

These data evidenced the significant prevalence of pertussis infection among paucy or poorly symptomatic contacts of infants with pertussis infection. Widespread usage of molecular testing should be implemented to identify B. pertussis infections.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06266-6.

Pediatric Infectious Disease Group (GPIP) position paper on the immune debt of the COVID-19 pandemic in childhood, how can we fill the immunity gap?

Since the beginning of the COVID-19 pandemic, reduced incidence of many viral and bacterial infections has been reported in children: bronchiolitis, varicella, measles, pertussis, pneumococcal and meningococcal invasive diseases. The purpose of this opinion paper is to discuss various situations that could lead to larger epidemics when the non-pharmaceutical interventions (NPI) imposed by the SARS-CoV-2 epidemic will no longer be necessary. While NPIs limited the transmission of SARS-CoV-2, they also reduced the spread of other pathogens during and after lockdown periods, despite the re-opening of schools since June 2020 in France. This positive collateral effect in the short term is welcome as it prevents additional overload of the healthcare system. The lack of immune stimulation due to the reduced circulation of microbial agents and to the related reduced vaccine uptake induced an "immunity debt" which could have negative consequences when the pandemic is under control and NPIs are lifted. The longer these periods of "viral or bacterial low-exposure" are, the greater the likelihood of future epidemics. This is due to a growing proportion of "susceptible" people and a declined herd immunity in the population. The observed delay in vaccination program without effective catch-up and the decrease in viral and bacterial exposures lead to a rebound risk of vaccine-preventable diseases. With a vaccination schedule that does not include vaccines against rotavirus, varicella, and serogroup B and ACYW Neisseria meningitidis, France could become more vulnerable to some of these rebound effects.

Transversal sero-epidemiological study of Bordetella pertussis in Tehran, Iran

Objectives

Pertussis remains endemic despite high vaccine coverage in infants and toddlers. Pertussis vaccines confer protection but immunity wanes overtime and boosters are needed in a lifetime. Iran, eligible for the Expanded Program on Immunization that includes the primary immunization, implemented two additional booster doses using a whole-cell vaccine (wPV) at 18 months-old and about 6 years-old. Duration of protection induced by the wPVs currently in use and their impact as pre-school booster are not well documented. This study aimed at assessing vaccination compliance and at estimating the duration of protection conferred by vaccination with wPV in children aged < 15 years in Tehran, Iran.

Methods

Detailed information on vaccination history and capillary blood samples were obtained from 1047 children aged 3–15 years who completed the 3 doses-primary pertussis immunization, in Tehran. Anti-pertussis toxin IgG levels were quantified by ELISA.

Results

Compliance was very high with 93.3% of children who received the three primary and 1^st booster doses in a timely manner. Timeliness of the 2^nd booster was lower (63.3%). Rate of seropositive samples continuously and significantly increased from 1–2 to 5–6 years after 1^st booster attaining 30.4% of children exhibiting serological sign of recent contact with B. pertussis. Second booster dating back 1 or 2 years was associated with high antibody titers, which significantly decreased within 3 years from injection. Among children who received 2^nd booster injection more than 2 years before serum analysis, seroprevalence of pertussis infection was 8.4% and seropositivity rate was higher from the 10 years-old group.

Conclusion

Seropositivity in children aged 6–7 years with no 2^nd booster supports the need for a vaccination at that age. Adolescent booster may also be considered.

Pertussis vaccination in mixed markets: Recommendations from the Global Pertussis Initiative

The Global Pertussis Initiative is an expert scientific forum that publishes consensus recommendations concerning pertussis for many regions of the world. Here, we give recommendations for the primary vaccination of infants in those countries where whole-cell pertussis (wP)- and acellular pertussis (aP)-containing combination vaccines are used in parallel. A selective literature review was performed concerning the influence on safety, immunogenicity, and effectiveness of mixing wP- and aP-containing vaccines for primary immunization of infants. In addition, local data were collected from various countries and the results discussed in a face-to-face meeting. Very few data addressing issues of mixing combination vaccines were identified, and no data were available concerning the effectiveness or duration of protection. It was also found that pharmacovigilance data are scarce or lacking in those countries where they would be needed the most. We then identified frequent problems occurring in low- and middle-income countries (LMICs) where both vaccine types are used. Relying on local knowledge, we give practical recommendations for a variety of situations in different settings. Specific needs for additional data addressing these issues were also identified. International bodies, such as the World Health Organization (WHO), as well as vaccine producers should try to find ways to highlight the problems of mixing wP- and aP-containing combination vaccines with robust data. Countries are urged to improve on their pharmacovigilance for vaccines. For practicing physicians, our recommendations offer guidance when wP- and aP-containing vaccines are used in parallel during primary immunization.

Pertussis in infants, in their mothers and other contacts in Casablanca, Morocco

BACKGROUND

In recent decades, there has been a marked increase in the number of reported cases of pertussis around the world, and pertussis continues to be a frequently occurring disease despite an effective childhood vaccination. This study aims to determine the role of household contacts of children diagnosed with pertussis in Casablanca Morocco.

METHODS

From November 2015 to October 2017, children suspected of whooping cough that consulted Ibn Rochd University hospital at Casablanca with their household contacts were enrolled in the study. Nasopharyngeal (NP) samples of the suspected children were analyzed by culture and RT-PCR. For the household contacts, NP and blood samples were collected and analyzed by RT-PCR and specific detection of pertussis toxin antibodies by ELISA, respectively.

RESULTS

During the study period, the survey was carried out on 128 infants hospitalized for pertussis suspicion and their families (N = 140). B. pertussis DNA was specifically detected in 73 (57%) samples, coexistence of B. pertussis and B. parapertussis DNA in 3 (2.3%) samples, coexistence of B. pertussis and B. holmesii DNA in 10 (7.81%) and only one (0.78%) sample was IS 481 RT-PCR positive without the possibility of determining the Bordetella species with the diagnostic tools used. Confirmations of Pertussis infection in household contacts by culture, RT- PCR and serology were 10, 46 and 39%, respectively. B. pertussis DNA was confirmed in the infants as well in their mothers in 38% of the cases. Co detection of B. pertussis and B. parapertussis DNA in 2% and co-detection of B. pertussis and B. holmesii DNA in 4%. B. holmesii DNA alone was detected in 5 NP samples of index cases and their mothers.

CONCLUSIONS

The results of this study confirm that B. pertussis is still circulating in children and adults, and were likely a source of pertussis contamination in infants still not vaccinated. The use of RT-PCR specific for B. pertussis in the diagnosis of adults is less sensitive and should be associated with serologic tests to improve diagnosis of pertussis and contributes to preventing transmission of the disease in infants.

Pertactin-Negative and Filamentous Hemagglutinin-Negative Bordetella pertussis, Australia, 2013-2017

During the 2008–2012 pertussis epidemic in Australia, pertactin (Prn)–negative Bordetella pertussis emerged. We analyzed 78 isolates from the 2013–2017 epidemic and documented continued expansion of Prn-negative ptxP3 B. pertussis strains. We also detected a filamentous hemagglutinin-negative and Prn-negative B. pertussis isolate.

Pertussis epidemiology in Tunisian infants and children and characterization of Bordetella pertussis isolates: results of a 9-year surveillance study, 2007 to 2016

PURPOSE

Pertussis remains a public health concern in most countries. Our study aimed to prospectively explore the epidemiology of pertussis in the Tunis area of Tunisia between 2007 and 2016, and to characterize the virulence-associated genes of the collected Bordetella pertussis isolates.

METHODOLOGY

Infants and children hospitalized at the Children's Hospital of Tunis, Tunisia, between 2007 and 2016 for suspicion of pertussis were enrolled in the study. Culture and real-time PCR (qPCR) assays targeting IS481, IS1001, recA, H-IS1001 and ptxP were used to confirm the pertussis diagnosis. Phenotypic and genotypic characterization of recovered isolates was performed.Results/Key findings. A total of 1844 children were included in the study. Overall, 306 children (16.6 %) with Bordetella infection were confirmed by qPCR. Among them, 265 (86.6 %) were confirmed as having B. pertussis (IS481+, ptxP+, H-IS1001-), 18 (5.9 %) as having Bordetella parapertussis (IS481-, IS1001+) and 11 (3.6 %) as having Bordetella spp. (IS481+, ptxP-, H-IS1001-). No Bordetella holmesii (IS481+, IS1001-, H-IS1001+) was identified. The estimated pertussis incidence in the Tunis area was 134/100 000 in children aged less than 5 years. Two epidemic peaks were observed in 2009 and 2014. Ten B. pertussis isolates were cultured and characterized. Deficiency in pertactin expression was not observed, and genotyping of the isolates revealed a predominant allelic profile: ptxP3-ptxA1-prn2-fim2-1-fim3-2.

CONCLUSION

This study demonstrated that pertussis is still present as a cyclical disease in Tunisia, despite high primo-vaccination coverage with a pertussis whole-cell vaccine. The predominant genotype of Tunisian B. pertussis isolates is similar to isolates circulating in countries using the acellular vaccine.

Diphtheria in Mayotte, 2007-2015

Epidemiology of diphtheria in the southwestern Indian Ocean is poorly documented. We analyzed 14 cases of infection with toxigenic Corynebacterium diphtheriae reported during 2007–2015 in Mayotte, a French department located in this region. Local control of diphtheria is needed to minimize the risk for importation of the bacterium into disease-free areas.

Incidence of pertussis in subjects aged 50years and older in France in 2013-2014

OBJECTIVE

To assess the incidence of pertussis (whooping cough) in subjects aged 50years and older in France.

METHODS

Participating family physicians (FPs) using the patient record management software AxiSanté^® included patients aged 50years and older, who had signed an informed consent form, presenting with persistent cough for 7 to 21days. Bordetella genetic material was detected by polymerase chain reaction (PCR) on nasopharyngeal samples collected at the FP's discretion.

RESULTS

A total of 42 FPs included 129 patients from June 2013 to August 2014 (large cities: 38; medium-sized cities: 57; rural areas: 34); 106 samples were analyzed. Overall, 30 pertussis cases were diagnosed: 10 cases confirmed by PCR, 18 purely clinical cases, and two direct epidemiological cases. The crude incidence rate per 100,000 patients aged≥50years was 103.6 (95% CI: 69.9-47.9): 77.1 in large cities, 103.1 in medium-sized cities, and 143.9 in rural areas. The extrapolated incidence rate per 100,000 persons aged≥50years was 187.1 (95% CI: 126.2-67.1): 131.1 in large cities, 256.1 in medium-sized cities, and 242.2 in rural areas.

CONCLUSION

The population aged 50years and older can serve as a reservoir. Its role in Bordetella pertussis circulation should be taken into account for pertussis booster vaccination programs.

Whooping cough surveillance in France in pediatric private practice in 2006-2015

BACKGROUND

Increasing incidence of whooping cough (pertussis) has been reported in many countries, attributed to a switch from whole-cell pertussis-containing vaccine (wPV) to acellular PV (aPV) and circulation of the pertactin non-producing Bordetella pertussis. The present study aimed to estimate the duration of immunity conferred by PVs in children in France with data from an ongoing pediatric ambulatory surveillance of pertussis.

METHODS

A total of 64 pediatricians throughout France enrolled children with suspected pertussis. A standardized data form was used to collect data on age sex, vaccination status, brand of wPV or aPV and source of infection. Confirmed cases were positive on culture and/or real-time Polymerase Chain Reaction (for B.-non-classified or B. pertussis or B. parapertussis) and/or pertussis serology.

RESULTS

Between October 2006 and December 2015, 149 cases of confirmed Bordetella infections were reported, 86 infected with B. pertussis and 55 B. non-classified. Fifteen children (10.1%) were not vaccinated, and 26 (17.4%) were partially vaccinated. The mean age was greater for children who received 4 doses of wPV (11.3±2.2, p<0.001) or a combination of wPV and aPV (10.5±3.3, p<0.001) than only aPV (7.2±2.4years). The mean duration of cough before a visit to a pediatrician was longer for children with wPV or a combination of wPV and aPV than only aPV (23.8±10.1 and 25.0±25.6vs 13.6±10.0days).

CONCLUSION

Despite the use of a more sensitive diagnostic method and emergence of pertactin non producing B. pertussis, in France context, aPV-induced immunity still protects against pertussis; however, the mean duration of immunity is about 6 to 7years, compared to 9years for wPV vaccine, after the primary vaccination and one booster (3+1 doses).

Characterization of Post-Translational Modifications and Cytotoxic Properties of the Adenylate-Cyclase Hemolysin Produced by Various Bordetella pertussis and Bordetella parapertussis Isolates

Bordetella pertussis and Bordetella parapertussis are the causal agents of whooping cough in humans. They produce diverse virulence factors, including adenylate cyclase-hemolysin (AC-Hly), a secreted toxin of the repeat in toxins (RTX) family with cyclase, pore-forming, and hemolytic activities. Post-translational modifications (PTMs) are essential for the biological activities of the toxin produced by B. pertussis. In this study, we compared AC-Hly toxins from various clinical isolates of B. pertussis and B. parapertussis, focusing on (i) the genomic sequences of cyaA genes, (ii) the PTMs of partially purified AC-Hly, and (iii) the cytotoxic activity of the various AC-Hly toxins. The genes encoding the AC-Hly toxins of B. pertussis and B. parapertussis displayed very limited polymorphism in each species. Most of the sequence differences between the two species were found in the C-terminal part of the protein. Both toxins harbored PTMs, mostly corresponding to palmitoylations of the lysine 860 residue and palmoylations and myristoylations of lysine 983 for B. pertussis and AC-Hly and palmitoylations of lysine 894 and myristoylations of lysine 1017 for B. parapertussis AC-Hly. Purified AC-Hly from B. pertussis was cytotoxic to macrophages, whereas that from B. parapertussis was not.

Bordetella Adenylate Cyclase-Hemolysin Toxins

Adenylate cyclase-hemolysin toxin is secreted and produced by three classical species of the genus Bordetella: Bordetella pertussis, B. parapertussis and B. bronchiseptica. This toxin has several properties such as: (i) adenylate cyclase activity, enhanced after interaction with the eukaryotic protein, calmodulin; (ii) a pore-forming activity; (iii) an invasive activity. It plays an important role in the pathogenesis of these Bordetella species responsible for whooping cough in humans or persistent respiratory infections in mammals, by modulating host immune responses. In contrast with other Bordetella toxins or adhesins, lack of (or very low polymorphism) is observed in the structural gene encoding this toxin, supporting its importance as well as a potential role as a vaccine antigen against whooping cough. In this article, an overview of the investigations undertaken on this toxin is presented.

The length of poly(C) stretch in the Bordetella pertussis Pfim3 promoter determines the vag or vrg function of the fim3 gene

Bordetella pertussis, a human pathogenic bacterium, produces either one or two types of serologically distinct fimbriae, Fim2 and Fim3, as virulence factors. The expression of fim2 and fim3 is regulated by the BvgAS two-component system and the length of poly(C) stretches in Pfim promoters. In the Bvg+ phase, B. pertussis virulence-activated genes (vags) are up-regulated and virulence-repressed genes (vrgs) are down-regulated. Previous studies have shown that fim2 is a vag, but there is no consensus on fim3 regulation. We examined the regulation of fimbrial expression in B. pertussis clinical isolates. Our findings indicate that fim2 is a vag, while fim3 is a vag when Pfim3 poly(C)>13C, and a vrg when poly(C)≤13C. Although increased fim3 expression was observed in the Bvg- phase in isolates with Pfim3 poly(C)≤13C, Fim3 production was not detected, suggesting post-transcriptional regulation of fim3 expression. These findings provide an insight into the regulation of fimbrial expression in B. pertussis.

Bordetella holmesii: Lipid A Structures and Corresponding Genomic Sequences Comparison in Three Clinical Isolates and the Reference Strain ATCC 51541

Bordetella holmesii can cause invasive infections but can also be isolated from the respiratory tract of patients with whooping-cough like symptoms. For the first time, we describe the lipid A structure of B. holmesii reference strain ATCC 51541 (alias NCTC12912 or CIP104394) and those of three French B. holmesii clinical isolates originating from blood (Bho1) or from respiratory samples (FR4020 and FR4101). They were investigated using chemical analyses, gas chromatography–mass spectrometry (GC–MS), and matrix-assisted laser desorption ionization–mass spectrometry (MALDI–MS). The analyses revealed a common bisphosphorylated β-(1→6)-linked d-glucosamine disaccharide with hydroxytetradecanoic acid in amide linkages. Similar to B. avium, B. hinzii and B. trematum lipids A, the hydroxytetradecanoic acid at the C-2′ position are carrying in secondary linkage a 2-hydroxytetradecanoic acid residue resulting of post-traductional biosynthesis modifications. The three clinical isolates displayed characteristic structural traits compared to the ATCC 51541 reference strain: the lipid A phosphate groups are more or less modified with glucosamine in the isolates and reference strain, but the presence of 10:0(3-OH) is only observed in the isolates. This trait was only described in B. pertussis and B. parapertussis strains, as well as in B. petrii isolates by the past. The genetic bases for most of the key structural elements of lipid A were analyzed and supported the structural data.

Epidemiology of pertussis in Casablanca (Morocco): contribution of conventional and molecular diagnosis tools

Background

Pertussis, a vaccine preventable disease, is still responsible of significant morbidity and mortality around the world, mostly in newborns. The aim of the present study was (1) to introduce pertussis surveillance in the major pediatric hospital of Casablanca (2) to analyze the prevalence of pertussis among children under 14 years of age and their entourage in Casablanca, Morocco.

Methods

This is a prospective and non-case controlled study, including children suspected of Pertussis admitted at the Abderrahim Harouchi Pediatric Hospital in Casablanca, from January 2013 to June 2015. Nasopharyngeal samples were obtained for Bordetella spp. culture and Real time PCR detection (RT-PCR) with specific primers of Bordetella spp., B. pertussis, B. parapertussis and B. holmesii. The detection of Bordetella spp. was also performed in some household contacts of the children suspected of pertussis.

Results

During the 2.5-years period, a total of 282 samples were collected from hospitalized children (156) and in some of their contacts (126). Among 156 samples from the children (from whom 57% were under 2 month of age), Bordetella DNA was detected in 61% (96/156) by RT-PCR. Among these positive samples, 91.7% (88/96) corresponded to B. pertussis DNA. Furthermore, in 39.5% (38/96) of the Bordetella positive samples, B. holmesii DNA was also detected. B. parapertussis DNA was detected in only one sample (1/156). Out of the 156 samples collected from the hospitalized children, only 48 were tested by culture, and 4 B. pertussis were isolated (8.3%). Among the 126 samples from the contacts of the children, mostly mothers (115 cases), Bordetella DNA was detected in 47% (59/126), 90% (53/59) being B. pertussis DNA. Moreover, B. holmesii DNA was also detected in 18.6% (11/59) of the Bordetella positive samples, and coexistence of B. pertussis and B. holmesii DNA in 36.5% (35/96). Two B. pertussis were isolated by culture performed on 43 samples of the contacts of the children (4.6%).

Conclusions

This study highlights the circulation of B. pertussis but also of B. holmesii in Casablanca-Morocco with a high proportion of co-infections B. holmesii/B. pertussis in infants and their mothers, indicate that infection of non-vaccinated infants could be more associated with young parents. Moreover, the RT- PCR provides a sensitive and specific diagnosis of B. pertussis infections and distinguishes it from other Bordetella species, and is therefore suitable for implementation in the diagnostic laboratory.

An unusual adenosine cyclic 3',5'-phosphate-dependent protein kinase from Dictyostelium discoideum

The CAMP-dependent protein kinase from Dictyostelium discoideum was extracted from cells at the stage of culmination. Less than 50% of the enzyme remains as a CAMP-dependent holoenzyme in the extracts, and the rest is recovered in the form of dissociated regulatory and catalytic subunits that were purified. The regulatory subunit is a monomeric protein of M, 42 000 that carries only one cAMP binding site (Kd = 3 nM). The catalytic subunit is also a monomer of M, 40000 with a sedimentation coefficient of 3.3S. The CAMP-dependent holoenzyme is a dimer consisting of one regulatory and one catalytic subunit, and the same structure is found for the holoenzyme reconstituted from the isolated subunits. Whereas cAMP binding to the regulatory subunit is independent of pH, both the catalytic activity and its ability to be inhibited by addition of regulatory subunit are increased very strongly between pH 5.5 and 7. The differences in molecular and catalytic properties of this CAMP-dependent protein kinase with those from mammalian origin are discussed in relation with the possibility that the enzyme from Dictyostelium represents an early form of the molecule in the evolutionary process.

Microbiological and molecular characterization of Corynebacterium diphtheriae isolated in Algeria between 1992 and 2015

The objectives of this study were to undertake the microbiological and molecular characterization of Corynebacterium diphtheriae isolates collected in Algeria during epidemic and post-epidemic periods between 1992 and 2015. Microbiological characterization includes the determination of biotype and toxigenicity status using phenotypic and genotypic methods. Antimicrobial susceptibility was determined by the E-test method. Molecular characterization was performed by multi-locus sequence typing. In total, there were 157 cases of C. diphtheriae isolates, 127 in patients with respiratory diphtheria and 30 with ozena. Isolates with a mitis biotype were predominant (122 out of 157; 77.7%) followed by belfanti (28 out of 157; 17.8%) and gravis biotype (seven out of 157; 4.5%). Toxigenic isolates were predominant in the period 1992-2006 (74 out of 134) whereas in the period 2007-2015, only non-toxigenic isolates circulated (23 out of 23). All 157 isolates were susceptible to erythromycin, gentamicin, vancomycin and cotrimoxazole. Reduced susceptibility to penicillin G, cefotaxime, tetracycline and chloramphenicol was detected in 90 (57.3%), 88 (56.1%), 112 (71.3%) and 90 (57.3%) isolates, respectively. Multi-locus sequence typing analysis indicates that sequence type 116 (ST-116) was the most frequent, with 65 out of 100 isolates analysed, in particular during the epidemic period 1992-1999 (57 out of 65 isolates). In the post-epidemic period, 2000-2015, 13 different sequence types were isolated. All belfanti isolates (ten out of 100 isolates) belonged to closely related sequence types grouped in a phylogenetically distinct eBurst group and were collected exclusively in ozena cases. In conclusion, the epidemic period was associated with ST-116 while the post-epidemic period was characterized by more diversity. Belfanti isolates are grouped in a phylogenetically distinct clonal complex.

Opportunistic Pulmonary Bordetella hinzii Infection after Avian Exposure

Diagnosing infections involving this species by routine methods is difficult.

We report 2 cases of pulmonary Bordetella hinzii infection in immunodeficient patients. One of these rare cases demonstrated the potential transmission of the bacteria from an avian reservoir through occupational exposure and its persistence in humans. We establish bacteriologic management of these infections and suggest therapeutic options if needed.

Health and Economic Consequences of an Outbreak of Pertussis Among Healthcare Workers in a Hospital in France

Background:

Bordetella pertussisis highly contagious, and because immunity wanes after vaccination, it continues to be a cause of cough among adults.

Objective:

To describe the healthcare services used and productivity losses accrued by healthcare workers (HCWs) missing work due to pertussis.

Methods:

After 3 pertussis cases were confirmed among HCWs, all hospital employees and patients with a cough were screened between November 2000 and March 2001. Each potential case underwent diagnostic tests and received antibiotics (spiramycin or azithromycin) when appropriate. Symptomatic employees were not allowed to return to work until they received an antibiotic for at least 5 days. Services used (physician visits and calls, antibiotics, diagnostic tests, hospitalization, and treatment provided to their contacts) were combined with cost estimates (in 2002 euros) for these services in France.

Results:

Ninety-one potential cases were identified (77 HCWs, 12 patients, and 2 family members). Of them, 89% received antibiotics and 22% had at least one contact who was also treated. Approximately half (55%) of the HCWs who were cases missed 5 days of work. Four patients were admitted to the hospital as a result of the infection. The average medical cost was 297 euros per potential case: diagnostic tests accounted for 32% and hospitalization for 31%. Total cost (medical and productivity) was 46,661 euros for 91 cases, 42% from productivity losses. An investigation to identify these potential cases also accrued additional costs.

Conclusion:

Serious adverse health and economic consequences arose from transmission of pertussis among HCWs, their families, and patients.

Surveillance of pertussis: methods and implementation

INTRODUCTION

Pertussis or whooping cough is a respiratory disease caused by Bordetella pertussis or, to a lesser extent, by B. parapertussis. Vaccines against pertussis have been widely used for more than 50 years and have led to a significant reduction of morbidity and mortality. However, even in countries with a high vaccine coverage, the disease is still not well controlled. Surveillance is urgently needed.

AREAS COVERED

This review summarizes surveillance methods and gives examples that may be used when setting up a surveillance program or analyzing an outbreak. Expert commentary: Pertussis surveillance is urgently required in order to define the burden of disease, to adapt vaccine strategies according to the type of pertussis vaccine used and to follow the evolution of the bacteria.

Draft Genome Sequences of Two Pathogenic Corynebacterial Species Isolated from Cows

The species Corynebacterium renale, Corynebacterium pilosum, and Corynebacterium cystitidis were initially thought to be the same species C. renale, but with different immunological types. These bacteria are the causative agent of cystitis, urethritis and pyelonephritis and are found usually as constituents of the normal flora in the lower urogenital tract of cattle. Therefore, we present the draft genome sequences of two pathogenic Corynebacterium species: C. renale CIP 52.96 and C. pilosum CIP 103422. The genome sequences of these species have 2,322,762 bp with 2,218 protein encoding genes and 2,548,014 bp with 2,428 protein encoding genes, respectively. These genomes can help clarify the virulence mechanisms of these unknown bacteria and enable the development of more effective methods for control.

[Whole cell protein profiling characterization of Corynebacterium diphtheriae clinical isolates collected from various infections]

INTRODUCTION

Corynebacterium diphtheriae can cause various infections such as diphtheria, wound infections, septic arthritis, bacteraemia and endocarditis. Different virulence properties of the isolates might be related to different virulence factors expressed by the isolates. The objective of this study was to explore whether whole cell protein profiling might be useful in prediction of pathogenic properties of C. diphtheriae isolates.

METHODS

C. disphtheriae isolates collected from diphtheria, invasive and local infections and from asymptomatic carriers in Poland, France, New Caledonia and Canada in 1950-2014 were investigated using whole cell protein profile analysis.

RESULTS

All the examined isolates were divided into two clades: A and B with similarity about 47%, but clade B was represented by only one isolate. The clade A was divided in two subclades A.I NS .II with similarity 53,2% and then into four groups: A.Ia, A.Ib, A.Ic and A.Id. The comparative analysis did not distinguish clearly toxigenic and nontoxigenic isolates as well as invasive and noninvasive isolates.

CONCLUSIONS

Whole cell protein profile analysis of C. diphtheria exhibits good concordance with other genotyping methods but this method is not able to distinguish clearly invasive from non-invasive isolates.

New Data on Vaccine Antigen Deficient Bordetella pertussis Isolates

Evolution of Bordetella pertussis is driven by natural and vaccine pressures. Isolates circulating in regions with high vaccination coverage present multiple allelic and antigenic variations as compared to isolates collected before introduction of vaccination. Furthermore, during the last epidemics reported in regions using pertussis acellular vaccines, isolates deficient for vaccine antigens, such as pertactin (PRN), were reported to reach high proportions of circulating isolates. More sporadic filamentous hemagglutinin (FHA) or pertussis toxin (PT) deficient isolates were also collected. The whole genome of some recent French isolates, deficient or non-deficient in vaccine antigens, were analyzed. Transcription profiles of the expression of the main virulence factors were also compared. The invasive phenotype in an in vitro human tracheal epithelial (HTE) cell model of infection was evaluated. Our genomic analysis focused on SNPs related to virulence genes known to be more likely to present allelic polymorphism. Transcriptomic data indicated that isolates circulating since the introduction of pertussis vaccines present lower transcription levels of the main virulence genes than the isolates of the pre-vaccine era. Furthermore, isolates not producing FHA present significantly higher expression levels of the entire set of genes tested. Finally, we observed that recent isolates are more invasive in HTE cells when compared to the reference strain, but no multiplication occurs within cells.

Draft Genome Sequences of Two Species of "Difficult-to-Identify" Human-Pathogenic Corynebacteria: Implications for Better Identification Tests

Non-diphtheriae Corynebacterium species have been increasingly recognized as the causative agents of infections in humans. Differential identification of these bacteria in the clinical microbiology laboratory by the most commonly used biochemical tests is challenging, and normally requires additional molecular methods. Herein, we present the annotated draft genome sequences of two isolates of “difficult-to-identify” human-pathogenic corynebacterial species: C. xerosis and C. minutissimum. The genome sequences of ca. 2.7 Mbp, with a mean number of 2,580 protein encoding genes, were also compared with the publicly available genome sequences of strains of C. amycolatum and C. striatum. These results will aid the exploration of novel biochemical reactions to improve existing identification tests as well as the development of more accurate molecular identification methods through detection of species-specific target genes for isolate's identification or drug susceptibility profiling.

Persistent Bordetella bronchiseptica infection in a child with cystic fibrosis: Relationship to bacterial phenotype

Bordetella bronchiseptica is an opportunistic bacteria infecting the respiratory tract of patients with cystic fibrosis. We present a case of B. bronchiseptica chronic pulmonary infection and documentation of some phenotypic attributes of the clinical isolates allowing the microorganism to induce progressive respiratory degradation and chronic sputum colonization. We recommend implementing adequate treatment aiming eradication from the first isolation of this bacterium. We advise for practices that minimize opportunities for zoonotic transmission of B. bronchiseptica from family pets.

Nosocomial Pertussis Outbreak Among Adult Patients and Healthcare Workers

We describe a pertussis outbreak among adult patients in a French general hospital following transmission from a healthcare worker. This index case transmitted pertussis to other healthcare workers, who, in turn, contaminated other staff and two immuno-suppressed patients. This raises questions about infection control.

Analysis of Bordetella pertussis clinical isolates circulating in European countries during the period 1998-2012

Despite more than 50 years of vaccination, pertussis is still an endemic disease, with regular epidemic outbreaks. With the exception of Poland, European countries have replaced whole-cell vaccines (WCVs) by acellular vaccines (ACVs) in the 1990s. Worldwide, antigenic divergence in vaccine antigens has been found between vaccine strains and circulating strains. In this work, 466 Bordetella pertussis isolates collected in the period 1998–2012 from 13 European countries were characterised by multi-locus antigen sequence typing (MAST) of the pertussis toxin promoter (ptxP) and of the genes coding for proteins used in the ACVs: pertussis toxin (Ptx), pertactin (Prn), type 2 fimbriae (Fim2) and type 3 fimbriae (Fim3). Isolates were further characterised by fimbrial serotyping, multi-locus variable-number tandem repeat analysis (MLVA) and pulsed-field gel electrophoresis (PFGE). The results showed a very similar B. pertussis population for 12 countries using ACVs, while Poland, which uses a WCV, was quite distinct, suggesting that ACVs and WCVs select for different B. pertussis populations. This study forms a baseline for future studies on the effect of vaccination programmes on B. pertussis populations.

Rapid increase in pertactin-deficient Bordetella pertussis isolates, Australia

Acellular vaccines against Bordetella pertussis were introduced in Australia in 1997. By 2000, these vaccines had replaced whole-cell vaccines. During 2008–2012, a large outbreak of pertussis occurred. During this period, 30% (96/320) of B. pertussis isolates did not express the vaccine antigen pertactin (prn). Multiple mechanisms of prn inactivation were documented, including IS481 and IS1002 disruptions, a variation within a homopolymeric tract, and deletion of the prn gene. The mechanism of lack of expression of prn in 16 (17%) isolates could not be determined at the sequence level. These findings suggest that B. pertussis not expressing prn arose independently multiple times since 2008, rather than by expansion of a single prn-negative clone. All but 1 isolate had ptxA1, prn2, and ptxP3, the alleles representative of currently circulating strains in Australia. This pattern is consistent with continuing evolution of B. pertussis in response to vaccine selection pressure.

Toxigenic Corynebacterium ulcerans in a fatal human case and her feline contacts, France, March 2014

In March 2014, a person in their eighties who was diagnosed with extensive cellulitis due to toxigenic Corynebacterium ulcerans died from multiple organ failure. Environmental investigation also isolated C. ulcerans in biological samples from two stray cats in contact with the case. This finding provides further evidence that pets can carry toxigenic C. ulcerans and may be a source of the infection in humans.

Other Bordetellas, lessons for and from pertussis vaccines

The Bordetella genus comprises nine species of which Bordetella pertussis and B. parapertussis are isolated from humans and are the most studied Bordetella species since they cause whooping cough. They both originate from B. bronchiseptica, which infects several mammals and immune compromised humans, but the intensive use of pertussis vaccines induced changes in B. pertussis and B. parapertussis populations. B. petrii and B. holmesii are other species of unknown reservoir and transmission pattern that have been described in humans. It is still unknown whether these species are pathogens for humans or only opportunistic bacteria but biological diagnosis has confirmed the presence of B. holmesii in human respiratory samples while B. petrii and the four other species have little implications for public health.