Molecular surveillance of pneumococcal carriage following completion of immunization with the 13-valent pneumococcal conjugate vaccine administered in a 3 + 1 schedule.

In a cross-sectional study, with the use of molecular methods, we aimed to gain insight into oropharyngeal pneumococcal colonization over time in 1212 Greek children recruited in general pediatric settings throughout the country; they were fully vaccinated with PCV13 (3 + 1 schedule). A single sample was obtained from each child at a time interval of 26 days to 70 months after administration of the 4th (booster) PCV13 dose; sampling time was divided into six time intervals. Carriage of Streptococcus pneumoniae was detected by real-time PCR targeting the lytA gene and isolates were serotyped by singleplex real-time PCR assays. Multiple control procedures to avoid false-positive results were applied. We showed an overall S. pneumoniae carriage rate of 48.6%. Serotyping identified typeable isolates in 82% of the total lytA-positive samples. Non-PCV13 serotypes represented 83.8% of total isolates when excluding serogroups with mixed PCV13 and non-PCV13 serotypes. In multivariate analysis daycare/school attendance emerged as the main contributing factor. Notably, serotypes 19A and 3 were the only two PCV13 serotypes the colonization rate of which increased over time (χ2 for trend P < 0.001 and P = 0.012, respectively). The application of the SP2020 gene on lytA-positive serotyped samples showed pneumococcal colonization in 97% of cases, and the overall colonization profile over time closely resembled that of the lytA gene. With the provisions of the methodological approach and age group of our study, the use of the oropharynx emerges as a reliable alternative to the nasopharynx in estimating pneumococcal carriage in epidemiological studies.

emm Types and clusters and macrolide resistance of pediatric group A streptococcal isolates in Central Greece during 2011-2017.

BACKGROUND: The surveillance of emm types and macrolide susceptibility of group A streptococcus (GAS) in various areas and time periods enhances the understanding of the epidemiology of GAS infections and may guide treatment strategies and the formulation of type-specific vaccines. Greece has emerged as a country with high macrolide use. However, studies suggest a gradual reduction in macrolide consumption after 2007. METHODS: During a 7-year period (2011-2017), 604 GAS isolates were recovered from consecutive children presenting with pharyngeal or nonpharyngeal infections in Central Greece; 517 viable isolates underwent molecular analysis, including emm typing. RESULTS: Isolates belonged to 20 different emm types (in decreasing order of prevalence: 1, 89, 4, 12, 28, 3, 75 and 6, accounting for 88.2% of total isolates). The emm types comprised 10 emm clusters (five most common clusters: E4, A-C3, E1, A-C4 and A-C5). The emm89 isolates were acapsular ('new clade'). Overall macrolide resistance rate was 15.4%, and cMLSB emerged as the predominant resistance phenotype (56.4%). The lowest annual resistance rates occurred in 2014 (13.1%), 2016 (5.5%) and 2017(8.0%) (P for trend = 0.002). Consumption of macrolide/lincosamide/streptogramin B declined by 22.6% during 2011-2017. Macrolide resistance and emm28 and emm77 types were associated (both P<0.001). The most frequently identified genetic lineages of macrolide-resistant GAS included emm28/ST52, emm77/ST63, emm12/ST36, emm89/ST101 and emm4/ST39. We estimated that 98.8% of the isolates belonged to emm types incorporated into a novel 30-valent M protein vaccine. CONCLUSIONS: In Central Greece during 2011-2017, the acapsular emm89 isolates comprised the second most prevalent type. Susceptibility testing and molecular analyses revealed decreasing GAS macrolide resistance rates, which may be attributed to the reduction in the consumption of macrolides and/or the reduced circulation of macrolide-resistant clones in recent years. Such data may provide valuable baseline information in targeting therapeutic intervention and the formulation of type-specific GAS vaccines.

Daptomycin Use in Children: Experience With Various Types of Infection and Age Groups.

BACKGROUND: In Greece, there are high rates of methicillin (40%-60%) and clindamycin (15%-25%) resistance among community-acquired Staphylococcus aureus isolates. Therefore, we sought to identify other antimicrobial treatment options such as daptomycin. METHODS: We studied retrospectively all pediatric infections treated with daptomycin at the University General Hospital of Larissa, Greece, from January 1, 2007, to June 16, 2016. RESULTS: Of a total of 128 patients (median age: 2.8 years; range: 8 days to 14.5 years; 76.6% <7 years) treated with daptomycin, 45 (35.2%) had invasive infection, most frequently musculoskeletal, and 83 (64.8%) had noninvasive infection, that is, complicated skin and soft tissue infection. S. aureus was the most commonly recovered pathogen (n = 61) (63.9% methicillin-resistant isolates, 21.3% clindamycin-resistant). The average daily dose of daptomycin was 10 mg/kg qd, and the median duration of therapy was 10 days. Daptomycin was administered alone (n = 61) or in combination therapy (n = 67), most frequently with rifampin (n = 40) and/or a ß-lactam antibiotic (n = 33). Open or closed drainage was performed in 86 (67.2%) of the total number of patients. Of 128 treated patients, 123 (96.1%) achieved clinical success, 114 (89.1%) had complete remission, and 9 (7%) had improvement of their disease. There were no failures with daptomycin therapy. The adverse events were of no clinical significance. CONCLUSIONS: Daptomycin administered alone or in combination with other antimicrobial agents to children was efficacious and well tolerated in the treatment of complicated infections of suspected or proven staphylococcal etiology.

Pneumonia with empyema among children in the first five years of high coverage with 13-valent pneumococcal conjugate vaccine.

BACKGROUND: Parapneumonic effusions in children are usually associated with pneumococcal infections. In Greece, the 7-valent pneumococcal conjugate vaccine was replaced by higher-valent pneumococcal conjugate vaccines (PCVs); 10-valent was introduced in May 2009 and 13-valent (PCV13) in June 2010. Since July 2010, PCV13 has been the most commonly used PCV. In a study conducted at the University General Hospital of Larissa, Central Greece, from January 2012 to January 2016, 85.7% of children born after the implementation of PCV13 and aged 24-59 months had received the complete series (3 + 1 immunization schedule) of PCV13. METHODS: We studied all paediatric community-acquired pneumonia cases with empyema hospitalized at the University General Hospital of Larissa from January 2008 to January 2016. RESULTS: There were 30 cases of parapneumonic empyema. Among 27 empyema cases of known aetiology, 19 (70.4%) were due to Streptococcus pneumoniae (identifiable serotypes 3, 19A, 7F, and 9N/L). After September 2011, no more cases caused by serotypes 7F and 19A were observed, whereas serotype 3 emerged as the predominant pathogen of pneumococcal empyema (9 of 11 cases). Serotype 3 continued to cause empyema despite vaccination with PCV13 either fully with a 3 + 1 schedule (n = 3) or with one booster dose at the age of 21 months (n = 1). CONCLUSION: In Central Greece during the first five years of high coverage with PCV13, serotype 3 was the only PCV13 serotype that clearly persisted in children with empyema.

Kingella kingae sequence type-complex 14 arthritis in a 16-month-old child in Greece.

We describe the first case of Kingella kingae arthritis in a 16-month-old girl in Greece, which has been diagnosed by novel molecular techniques. A joint aspiration of her knee was performed before the initiation of antibiotics, as well as on the 5th and 14th day of empiric antimicrobial therapy. The synovial fluid white blood cell count decreased from 65,000 to 1500 cells/mm, but the percentage of neutrophils remained 90% in all 3 specimens. Molecular analysis of the synovial fluid specimens by real-time polymerase chain reaction and multilocus sequence typing enabled us to reveal the presence of K. kingae belonging to the international sequence type-complex 14, which persisted up to the fifth day of antibiotic therapy.

Dynamics of pneumococcal carriage among day-care center attendees during the transition from the 7-valent to the higher-valent pneumococcal conjugate vaccines in Greece.

BACKGROUND: In Greece recently, higher-valent pneumococcal conjugate vaccines (PCVs) replaced the 7-valent (PCV7); the 10-valent (PCV10) became available in May 2009 and the 13-valent (PCV13) in June 2010. METHODS: We investigated the nasopharyngeal colonization with Streptococcus pneumoniae in day-care center attendees in Athens and the prefecture of Viotia. Between December 2010 and June 2011, nasopharyngeal cultures were obtained 4 times, at enrollment and then every 6 to 8 weeks. RESULTS: Among the 233 children, 225 (96.6%) had been vaccinated with ≥1 dose of PCV7. One tenth of the PCV7 vaccinated attendees had also received ≥1 dose of PCV13 or PCV10. During the 4 samplings, 358 isolates were recovered from a total of 874 samples. Of the 233 children, 183 (78.5%) were found to carry S. pneumoniae at least once. The overall serotype distribution among carriers was similar regardless of the time lapsed since the last PCV7 dose. A high frequency of 19A (17.1%) coincided with a low frequency of 19F (1.4%). Non-PCV13 serotypes accounted for 73.1% of the isolates; 23B, 15B/C, 16F, 21, 11A, 15A, 6C, 10A, 22F and 23A were the most common. Among attendees aged 24-59 months (median age 42 months), prolonged carriage of a non-PCV13 serotype was relatively common, mainly for 21 and 16F. One out of 4 cases of colonization with the prevalent non-PCV13 serotypes was followed by persistent carriage for 5 to 14 weeks. CONCLUSIONS: During this period of transition to the higher-valent PCVs in the day-care center setting, non-PCV13 serotypes dominated and exhibited prolonged colonization. The frequency and the duration of prolonged carriage tends to be increased, if sampling frequency increases and the carriage time before and after positive cultures is taken into consideration. Further studies regarding the fitness of the colonizing non-PCV13 serotypes will likely to be seen in the future.

European ST80 community-associated methicillin-resistant Staphylococcus aureus orbital cellulitis in a neonate.

BACKGROUND: Methicillin-resistant Staphylococcus aureus is a serious cause of morbidity and mortality in hospital environment, but also, lately, in the community. This case report is, to our knowledge, the first detailed description of a community-associated methicillin-resistant S. aureus ST80 orbital cellulitis in a previously healthy neonate. Possible predisposing factors of microbial acquisition and treatment selection are also discussed. CASE PRESENTATION: A 28-day-old Caucasian boy was referred to our hospital with the diagnosis of right orbital cellulitis. His symptoms included right eye proptosis, periocular edema and redness. Empirical therapy of intravenous daptomycin, rifampin and ceftriaxone was initiated. The culture of pus yielded a methicillin-resistant S. aureus isolate and the molecular analysis revealed that it was a Panton-Valentine leukocidine-positive ST80 strain. The combination antimicrobial therapy was continued for 42 days and the infection was successfully controlled. CONCLUSIONS: Clinicians should be aware that young infants, even without any predisposing condition, are susceptible to orbital cellulitis caused by community-associated methicillin-resistant S. aureus. Prompt initiation of the appropriate empirical therapy, according to the local epidemiology, should successfully address the infection, preventing ocular and systemic complications.

Dynamics of Streptococcus pneumoniae nasopharyngeal carriage with high heptavalent pneumococcal conjugate vaccine coverage in Central Greece.

In order to study whether the use of the heptavalent pneumococcal conjugate vaccine (PCV7) led to a shift in the Streptococcus pneumoniae serotypes distribution and whether it modified the resistance to antibiotics, 2649 nasopharyngeal samples were obtained between 2005 and 2009, from children attending day-care centers in Central Greece. The percentage of attendees vaccinated with ≥1 dose of PCV7 increased from 12.9% (2005) to 95.5% (2009). Non-PCV7 serotypes replaced those belonging to PCV7. In 2009, 19F was virtually the only PCV7 serotype that continued to circulate. A significant increase in the frequency of penicillin-intermediate (oral penicillin V breakpoints) isolates coincided with a marked reduction in isolates with high resistance to penicillin. Several non-PCV7 serotypes colonized the children, but their frequency varied substantially from year to year. Each one of 14 specific non-PCV7 serotypes, i.e. 6A, 11A, 15B, 23A, 10A, 16F, 38, 22F, 15C, 19A, 35F, 24F, 6C, and 7F, accounted for ≥2% of pneumococcal isolates in at least 2 annual surveillances. An increase in non-PCV7 serotypes with antibiotic resistance, beyond 6A and 19A, occurred. Intermediate resistance to penicillin was observed in serotype 23B, 15B, 15C, 15A, 35F, 6C, and 24F pneumococci. Their exact role in invasive and non-invasive disease remains to be seen in the years ahead.