Pertussis: infection, vaccination and gene polymorphisms

Pertussis or whooping cough is a human respiratory tract infection and a vaccine-preventable disease that is caused by Bordetella pertussis bacteria. Pertussis vaccination has been part of the Finnish national vaccine program since 1952. Despite extensive vaccinations, the incidence of pertussis has increased in many countries during the last decades. Large epidemics have been observed also in countries with high vaccine coverage. Inter-individual variation in immune responses is always encountered after vaccination. Low vaccine responses may cause vulnerability to pertussis even straight after vaccination. Reasons for low responses are not fully understood. The innate immune system is responsible for the initial recognition of pathogens and vaccine antigens. The role of innate immunity on pertussis immunity has not been thoroughly investigated. Mannose-binding lectin (MBL) and toll-like receptor 4 (TLR4) are important molecules of the innate immune system and in the recognition of pathogens. Cytokines form a signaling network that have a notable role in immune responses after infections as well as after vaccinations. Single nucleotide polymorphism (SNP) is common in genes encoding these molecules and the polymorphisms have been reported to affect vaccine response after viral and bacterial vaccines. This study investigated the gene polymorphisms of MBL2, TLR4 and interleukin (IL)-10 promoter and their association with vaccine responses after acellular pertussis (aP) vaccination in Finnish adolescents and infants. Cell-mediated immune responses were investigated ten years after the previous pertussis vaccinations in young adults. In addition, the role of MBL deficiency in pertussis infection susceptibility was evaluated. The results of this study show that subjects with TLR4 polymorphism had lower antibody production and persistence after aP vaccination compared with normal allele. A specific SNP in the TLR4 gene was associated with decreased antibody responses and persistence in adolescents after aP booster vaccination. Cell-mediated immune responses were partly detected ten years after the previous vaccination; booster vaccine clearly enhanced the responses. In addition, subjects with IL-10 polymorphism had altered cell-mediated immune responses. MBL deficiency was found to be more frequent in pertussis patients than healthy controls but the polymorphism of MBL2 was not associated with antibody responses after acellular pertussis vaccination. The novel finding of this study was that genetic variation in the innate immune system seems to play a role in altered pertussis vaccine responses as well as in pertussis infection. These new findings enlighten the mechanisms behind the low responses after pertussis vaccination and help to predict risk factors related to this phenomenon.Hinkuyskä: infektio, rokottaminen ja geenien vaihtelu Hinkuyskä on Bordetella pertussis –bakteerin aiheuttama hengitystieinfektio, jota vastaan on Suomessa rokotettu jo vuodesta 1952. Hinkuyskän esiintyvyys on noussut useissa maissa siitä huolimatta, että näissä maissa on saavutettu korkea rokotekattavuus. Laajoja epidemioita on havaittu myös näissä maissa, joissa rokotekattavuus on korkea. Kuten yleensä rokotuksilla, myös hinkuyskärokotuksen yhteydessä havaitaan rokotevasteissa yksilöiden välistä vaihtelua. Syytä alhaiseen rokotevasteeseen ei täysin tunneta. Luontainen immuniteetti muodostaa ensivasteen patogeenejä vastaan. Lisäksi se osallistuu rokoteantigeenien tunnistamiseen. Luontaisen immunteetin osuutta elimistön puolustuksessa hinkuyskää vastaan on tutkittu vain vähän. Mannosia sitova lektiini (MBL) ja tollin kaltainen reseptori 4 (TLR4) ovat tärkeitä luontaisen immuniteetin molekyylejä, jotka osallistuvat patogeenien tunnistamiseen. Interleukiinit (IL) ovat sytokiineihin kuuluvia signalointimolekyylejä, joiden muodostamilla signaalinvälitysketjuilla on merkittävä rooli immuunipuolustuksessa. Monimuotoisuus eli polymorfia on yleistä näitä molekyylejä koodaavissa geeneissä ja osan näistä polymorfioista on huomattu vaikuttavan rokotevasteisiin virus- ja bakteerirokotteiden yhteydessä. Tässä väitöskirjassa tutkittiin MBL2-, TLR4- ja IL-10 geenipolymorfian yhteyttä rokotevasteisiin hinkuyskärokotteen jälkeen suomalaisilla nuorilla aikuisilla sekä lapsilla. Hinkuyskäspesifisen soluvälitteisen immuunivasteen kehittymistä seurattiin kymmenen vuoden aikajänteellä. Lisäksi selvitettiin lisääkö MBL-proteiinin puutos alttiutta hinkuyskäinfektiolle. Tulokset osoittavat, että soluttoman hinkuyskärokotteen jälkeen tutkimukseen osallistuneista henkilöistä niillä, jotka kantavat TLR4 geenipolymorfiaa, oli alentunut hinkuyskäspesifinen vasta-aineiden tuotanto ja pysyvyys, verrattuna normaaliin geenimuodon kantajiin. Soluvälitteinen immuniteetti säilyi osittain kymmenen vuotta edellisestä rokotteesta ja tehosterokote nosti soluvälitteistä immuunivastetta merkittävästi. Lisäksi havaittiin ero soluvälitteisen immuniteetin vasteissa IL-10 geenipolymorfiaa kantavien ja normaalin geenimuodon kantajien välillä. Hinkuyskäpotilailla puolestaan löydettiin useammin MBL-proteiinin puutos kontrolliryhmään verrattuna, mutta MBL2 geenipolymorfia ei vaikuttanut hinkuyskärokotevasteisiin. Väitöskirjan tulokset viittaavat siihen, että geneettinen vaihtelu luontaisen immuniteetin molekyyleissä vaikuttaa sekä rokotevasteisiin soluttoman hinkuyskärokotteen jälkeen että hinkuyskäinfektioalttiuteen. Tutkimuksen tulokset auttavat ymmärtämään mekanismeja ja ennakoimaan riskitekijöitä, jotka vaikuttavat poikkeavaan rokotevasteeseen ja infektioalttiuteen.Siirretty Doriast

Low rate of asymptomatic carriage and salivary immunoglobulin A response to Group A Streptococci in the healthy adult population in Finland

Streptococcus pyogenes, also called group A streptococcus (GAS), is a human pathogen causing a wide range of infections ranging from mild tonsillitis to severe, life threatening conditions such as bacteraemia, necrotizing fasciitis, and streptococcal toxic shock syndrome. GAS may also colonise the oropharynx without causing any signs of disease which is known as asymptomatic carriage. This study aims to investigate IgA responses against GAS and oral streptococci from saliva samples collected from healthy Finnish adults. In addition, asymptomatic throat GAS carriage was studied. The study participants consisted of healthy adult volunteers who provided one saliva sample, a throat swab, and a background questionnaire. Total salivary IgA, and GAS specific IgA were analysed from the saliva samples using enzyme-linked immunosorbent assays (ELISA) and the results were compared to oral streptococci specific IgA levels. Asymptomatic GAS throat carriers were identified by bacterial culture, and the isolates were emm typed. Samples from a total of 182 individuals were analysed. The median salivary IgA concentration was 62.9 mu g/ml (range 17.3-649.9 mu g/ml), and median GAS and oral streptococcal specific IgA concentrations 2.7 and 3.3 arbitrary units (AU, range 1.4-7.4 AU and 1.6-12.0 AU), respectively. Three individuals with asymptomatic GAS throat carriage were identified

Performance of the Check-Direct ESBL Screen for BD MAXTM for detection of asymptomatic faecal carriage of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae

ObjectivesAccurte diagnostic methods are crucial for the detection of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E). Besides culture-based gold-standard methods, new molecular gene detection tests are reaching the market. The aim of this study was to investigate the performance of the direct quantitative PCR (qPCR)-based methods Check-Direct ESBL and CPE Screen for BD MAXTM in relation to traditional culture-based methods for detection of ESBL-E faecal carriage.MethodsFaecal samples were collected from healthy adult volunteers. Samples were cultured on chromogenic ESBL agar plates and were screened for ESBL-producing Escherichia coli and Klebsiella pneumoniae. Confirmed ESBL- and AmpC-producing isolates were further analysed using whole-genome sequencing. In addition, faecal samples were analysed using Check-Direct ESBL and CPE Screen for BD MAXTM and the results were compared with the gold-standard culture-based method.ResultsOf 176 faecal samples examined, 11 (6.3%) grew ESBL-producing E. coli or K. pneumoniae isolates. Among 173 analysed samples, Check-Direct ESBL Screen for BD MAXTM detected 22 (12.7%) ESBL-positive samples. No carbapenemase-producing isolates were detected. Two culture-positive samples remained negative with Check-Direct ESBL Screen for BD MAXTM. Culture-negative but qPCR-positive discrepancy was observed in 12 samples (6.9%). Altogether, concordant results were obtained for 158 samples (91.3%; 9 positive and 149 negative).ConclusionCheck-Direct ESBL Screen for BD MAXTM is a fast screening method for ESBL carriage. However, several discrepant results were observed, which hinders interpretation. More clinical samples should be tested in combination with culture to evaluate the true benefits of this method.</div

Group A streptococcal bacteremias in Southwest Finland 2007–2018: epidemiology and role of infectious diseases consultation in antibiotic treatment selection

The incidence of invasive group A streptococcal (GAS) infections has shown a fluctuating but increasing trend in Finland. The impact of infectious diseases specialist consultation (IDSC) on the antimicrobial therapy of GAS bacteremia has not been studied earlier. A retrospective study on adult GAS bacteremia in The Hospital District of Southwest Finland (HDSWF) was conducted from 2007 to 2018. Data on incidence of bacteremic GAS cases were gathered from the National Infectious Disease Register. Clinical data were obtained by reviewing the electronic patient records. The overall incidence of GAS bacteremia in HDSWF was 3.52/100,000, but year-to-year variation was observed with the highest incidence of 7.93/100,000 in 2018. A total of 212 adult GAS bacteremia cases were included. A record of IDSC was found (+) in 117 (55.2%) cases, not found (-) in 71 (33.5%) cases and data were not available in 24 (11.3%) cases. Among IDSC+ cases, 57.3% were on penicillin G treatment whereas in the group IDSC- only 22.5%, respectively (OR = 4.61, 95% CI 2.37-8.97; p < 0.001). The use of clindamycin as adjunctive antibiotic was more common among IDSC+ (54.7%) than IDSC- (21.7%) (OR = 4.51, 95% CI 2.29-8.87; p < 0.001). There was an increasing trend in incidence of GAS bacteremia during the study period. Narrow-spectrum beta-lactam antibiotics were chosen, and adjunctive clindamycin was more commonly used, if IDSC took place. This highlights the importance of availability of IDSC but calls for improved practice among infectious diseases specialists by avoiding combination therapy with clindamycin in non-severe invasive GAS infections

Genetic evolution of invasive emm28 Streptococcus pyogenes strains and significant association with puerperal infections in young women in Finland

Objectives: Streptococcus pyogenes or group A streptococcus (GAS) is a human specific pathogen that annually infects over 700 million individuals. GAS strains of type emm28 are an abundant cause of invasive infections in Europe and North America.Methods: We conducted a population-based study on bacteraemic emm28 GAS cases in Finland, from 1995 to 2015. Whole-genome sequencing (WGS) was used to genetically characterize the bacterial isolates. Bayesian analysis of the population structure was used to define genetic clades. Register-linkage analysis was performed to test for association of emm28 GAS with delivery- or postpartum-related infections. A genome-wide association study was used to search for DNA sequences associated with delivery or puerperal infections.Results: Among 3060 bacteraemic cases reported during the study period, 714 were caused by emm28. Women comprised a majority of cases (59 %, 422/714), and were significantly over-represented (84.4 %, 162/192, p Conclusions: Women of childbearing age were significantly overrepresented among bacteraemic emm28 GAS cases, and in particular were strongly associated with delivery and puerperium cases over the 21 years studied. The molecular mechanisms behind these associations are unclear and warrant further investigation.</p

IL-10 Gene Polymorphisms Are Associated with Post-Bronchiolitis Lung Function Abnormalities at Six Years of Age

Aim Interleukin-10 (IL-10) has been associated with wheezing and asthma in children and the genetic variation of the IL-10 cytokine production may be linked to post-bronchiolitis lung function. We used impulse oscillometry (IOS) to evaluate the associations of IL10 polymorphisms with lung function at a median age of 6.3 years in children hospitalised for bronchiolitis before six months of age. Methods We performed baseline and post-exercise IOS on 103 former bronchiolitis patients. Data on single nucleotide polymorphisms (SNP) of IL10 rs1800896 (–1082G/A), rs1800871 (–819C/T), rs1800872 (–592C/A) were available for 99 children and of IL10 rs1800890 (–3575T/A) for 98 children. Results IL10 rs1800896, rs1800871 and rs1800872 combined genotype AA+CT+CA and carriage of haplotype ATA, respectively, were associated with higher resistance and lower reactance in baseline IOS in adjusted analyses. At IL10 rs1800890, the A/A-genotype and carriers of A-allele were associated with lower reactance in baseline IOS. There were no significant associations between the studied SNPs and airway hyper-reactivity to exercise. Conclusion Low-IL-10-producing polymorphisms in the IL-10 encoding gene were associated with obstructive lung function parameters, suggesting an important role for IL-10 in development of lung function deficit in early bronchiolitis patients.Public Library of Science open acces

Detection of group A streptococcus in children with confirmed viral pharyngitis and antiviral host response

Our aim was to study the detection of group A streptococcus (GAS) with different diagnostic methods in paediatric pharyngitis patients with and without a confirmed viral infection. In this prospective observational study, throat swabs and blood samples were collected from children (age 1-16 years) presenting to the emergency department with febrile pharyngitis. A confirmed viral infection was defined as a positive virus diagnostic test (nucleic acid amplification test [NAAT] and/or serology) together with an antiviral immune response of the host demonstrated by elevated (>= 175 mu g/L) myxovirus resistance protein A (MxA) blood concentration. Testing for GAS was performed by a throat culture, by 2 rapid antigen detection tests (StrepTop and mariPOC) and by 2 NAATs (Simplexa and Illumigene). Altogether, 83 children were recruited of whom 48 had samples available for GAS testing. Confirmed viral infection was diagnosed in 30/48 (63%) children with febrile pharyngitis. Enteroviruses 11/30 (37%), adenoviruses 9/30 (30%) and rhinoviruses 9/30 (30%) were the most common viruses detected. GAS was detected by throat culture in 5/30 (17%) with and in 6/18 (33%) patients without a confirmed viral infection. Respectively, GAS was detected in 4/30 (13%) and 6/18 (33%) by StrepTop, 13/30 (43%) and 10/18 (56%) by mariPOC, 6/30 (20%) and 9/18 (50%) by Simplexa, and 5/30 (17%) and 6/18 (30%) patients by Illumigene.Conclusion: GAS was frequently detected also in paediatric pharyngitis patients with a confirmed viral infection. The presence of antiviral host response and increased GAS detection by sensitive methods suggest incidental throat carriage of GAS in viral pharyngitis.</p

Changing epidemiology of methicillin-resistant Staphylococcus aureus in a low endemicity area- new challenges for MRSA control

The incidence of methicillin-resistant Staphylococcus aureus (MRSA) has increased sharply in Hospital District of Southwest Finland (HD). To understand reasons behind this, a retrospective, population-based study covering 10 years was conducted. All new 983 MRSA cases in HD from January 2007 to December 2016 were analysed. Several data sources were used to gather background information on the cases. MRSA cases were classified as healthcare-associated (HA-MRSA), community-associated (CA-MRSA), and livestock contact was determined (livestock-associated MRSA, LA-MRSA). Spa typing was performed to all available strains. The incidence of MRSA doubled from 12.4 to 24.9 cases/100000 persons/year. The proportion of clinical infections increased from 25 to 32% in the 5-year periods, respectively, (p </p

Antimicrobial resistance of Escherichia coli isolates from outpatient urinary tract infections in women in six European countries including Russia

Objectives In the Northern Dimension Antibiotic Resistance Study (NoDARS), Finland, Germany, Latvia, Poland, Russia and Sweden collected urine samples from outpatient women (aged 18–65 years) with symptoms of uncomplicated urinary tract infection (UTI) to investigate the levels of antimicrobial resistance (AMR) among Escherichia coli isolates. Methods A total of 775 E. coli isolates from 1280 clinical urine samples were collected from October 2015 to January 2017. Antimicrobial susceptibility testing was performed and the results were interpreted according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. Results Overall AMR rates to the commonly used antibiotics nitrofurantoin, fosfomycin and mecillinam (except for Germany that was missing a result for mecillinam) were 1.2%, 1.3% and 4.1%, respectively. The highest overall resistance rates were determined for ampicillin (39.6%), trimethoprim (23.8%), trimethoprim/sulfamethoxazole (22.4%), amoxicillin/clavulanic acid (16.7%) and ciprofloxacin (15.1%), varying significantly between countries. The rate of extended-spectrum β-lactamase (ESBL) production was 8.7%. None of the isolates showed resistance to meropenem. Conclusions In most cases, low AMR rates were detected against the first-line antibiotics recommended in national UTI treatment guidelines, giving support to their future use. These results also support the European Association of Urology guidelines stating that nitrofurantoin, fosfomycin and mecillinam are viable treatment options for uncomplicated UTI.Peer Reviewe

Nasopharyngeal Bacterial Colonization and Gene Polymorphisms of Mannose-Binding Lectin and Toll-Like Receptors 2 and 4 in Infants

BACKGROUND: Human nasopharynx is often colonized by potentially pathogenic bacteria. Gene polymorphisms in mannose-binding lectin (MBL), toll-like receptor (TLR) 2 and TLR4 have been reported. The present study aimed to investigate possible association between nasopharyngeal bacterial colonization and gene polymorphisms of MBL, TLR2 and TLR4 in healthy infants. METHODOLOGY/PRINCIPAL FINDINGS: From August 2008 to June 2010, 489 nasopharyngeal swabs and 412 blood samples were taken from 3-month-old healthy Finnish infants. Semi-quantitative culture was performed and pyrosequencing was used for detection of polymorphisms in MBL structural gene at codons 52, 54, and 57, TLR2 Arg753Gln and TLR4 Asp299Gly. Fifty-nine percent of subjects were culture positive for at least one of the four species: 11% for Streptococcus pneumoniae, 23% for Moraxella catarrhalis, 1% for Haemophilus influenzae and 25% for Staphylococcus aureus. Thirty-two percent of subjects had variant types in MBL, 5% had polymorphism of TLR2, and 18% had polymorphism of TLR4. Colonization rates of S. pneumoniae and S. aureus were significantly higher in infants with variant types of MBL than those with wild type (p = .011 and p = .024). Colonization rates of S. aureus and M. catarrhalis were significantly higher in infants with polymorphisms of TLR2 and of TLR4 than those without (p = .027 and p = .002). CONCLUSIONS: Our study suggests that there is an association between nasopharyngeal bacterial colonization and genetic variation of MBL, TLR2 and TLR4 in young infants. This finding supports a role for these genetic variations in susceptibility of children to respiratory infections