Molecular analysis of Streptococcus pyogenes macrolide resistance of paediatric isolates during a 7 year period (2007-13).

OBJECTIVES: The molecular characterization of paediatric group A Streptococcus (GAS) isolates regarding macrolide resistance and relevant emm types in Athens, Greece. METHODS: Pharyngeal and non-pharyngeal GAS isolates were collected during a 7 year period (2007-13) and examined for antibiotic susceptibility, macrolide resistance genes [mef(A), erm(A) and erm(B)] and relevant emm types. RESULTS: Overall, 20.4% (270/1324) of GAS isolates were resistant to macrolides. The macrolide resistance rate varied during the study period with a maximum rate observed in 2008 (29.57%) and a minimum rate observed in 2013 (10.95%) (P value for trend = 0.007). During the same period, consumption of macrolides was gradually reduced by 56.6%. No difference was observed in macrolide resistance between pharyngeal and non-pharyngeal isolates (P = 0.7). Among macrolide-resistant isolates, mef(A) was detected in 87 (32.2%), erm(A) in 136 (50.4%), erm(B) in 44 (16.3%) and both mef(A) and erm(A) in 3 (1.1%) isolates. The most prevalent emm types among macrolide-resistant isolates were emm77 (31.5%), emm4 (18.1%) and emm12 (10.7%). Ten emm types (77, 4, 12, 28, 1, 22, 11, 2, 44 and 89) accounted for 90.3% of macrolide-resistant isolates. emm types 4, 22, 44 and 77 were more prevalent in macrolide-resistant compared with macrolide-susceptible isolates, whereas emm types 1, 3, 5, 6, 75 and 89 were more prevalent in macrolide-susceptible compared with macrolide-resistant isolates. CONCLUSIONS: GAS macrolide resistance remained significant in our area during the study period. A substantial decline in the resistance rate was observed in the last year of the study, which may be related to reduced consumption of macrolides.

Evolution of macrolide resistance in Streptococcus pneumoniae clinical isolates in the prevaccine era.

Six hundred twelve invasive and noninvasive Streptococcus pneumoniae isolates were examined. Serogrouping was performed by the latex agglutination test and serotyping by the quellung reaction. Susceptibilities to macrolides were determined by Etest. The presence of mef(A), mef(E), and erm(B) genes were detected by polymerase chain reaction. Outpatient macrolide and lincosamide consumption was expressed in defined daily doses per 1000 inhabitants daily (DID). A significant increase in macrolide resistance rate was noted from 7.4% (14/190) in the period 1985 to 1996 to 53.7% (144/268) in 2001 to 2004 (P = 0.003). An increase in macrolide and lincosamide consumption was also observed from 4.31 +/- 0.72 in 1990 to 1996 to 6.97 +/- 1.02 DID in 2001 to 2004 (P = 0.002). Macrolide resistance was mediated by mef(E) gene in 44.5% of isolates, mef(A) in 25.6%, erm(B) in 19.8%, both erm(B) and mef(E) genes in 4.8%, and none of the examined genes in 5.3%. In the setting of increasing macrolide use, there has been a parallel increase in macrolide resistance among pneumococci in our region. The predominant resistance determinants were the mef(A) and mef(E) genes.

Characteristics of Streptococcus pneumoniae serotype 19A isolates from children in the pre and post Conjugate Vaccine Era. Single center experience 1986-2015.

BACKGROUND: The present study assessed the prevalence and characteristics of S. pneumoniae serotype 19A isolates from children with pneumococcal disease (PD), before and since introduction of pneumococcal conjugate vaccines (PCVs) in Greece. METHODS: S. pneumoniae isolates collected at one large pediatric hospital between 1986 and 2015 were serotyped by the Quellung reaction and MICs determined by Etest. Alterations of pbp genes and the presence of mefA, mefE, ermB genes were detected by polymerase chain reaction. Genotypes were assessed by multilocus sequence typing (MLST). RESULTS: Among 1875 isolates, 210 (11.2%) belonged to serotype 19A. The prevalence of PD caused by serotype 19A increased from 4.6% in the pre-PCV7 years (1986-2005) to 19.6% in the post-PCV7 years (2006-2010), peaking at 27% in 2009 (p < 0.001, 95% CI; 2.0, 18.2) with a significant upward trend (p = 0.04, 95% CI; 1.02, 12.66). Following the introduction of PCV13 in 2010, the rate decreased from 22% in 2011 to 11.4% in 2015 (p = 0.08, 95% CI; 0.92, 5.1) with a downward trend of borderline significance (p = 0.05, 95% CI; -6.8, 0.04). The multidrug resistant (MDR) serotype 19A isolates increased from 10.6% in 1986-2005 to 21.2% in 2006-2010 and to 71.8% in 2011-2015 (P < 0.001). Alterations in pbp genes were detected in all penicillin non-susceptible isolates. Of 110 erythromycin resistant isolates, 21 contained the mefE gene, 36 the ermB and 53 both the mefE and ermB genes. MLST analysis of 142 isolates revealed four dominant clonal complexes (CC); CC320, CC172, CC276 and CC199. The majority of CC320 and CC276 isolates displayed MDR phenotypes. CONCLUSION: PD caused by serotype 19A increased significantly after the introduction of PCV7 followed by a decline after PCV13 use. The vast majority of persisting 19A isolates was MDR. Surveillance studies are necessary to monitor the changes in the pneumococcal population.

Detection of bacterial pathogens in synovial and pleural fluid with the FilmArray Blood Culture Identification System.

We report the use of FilmArray Blood Culture Identification (BCID) multiplex PCR system for pathogen detection from a child with septic arthritis that Streptococcus pyogenes was identified directly from synovial fluid and a child with complicated pneumonia with pleural effusion that Streptococcus pneumoniae was identified from pleural fluid.

Pneumococcal Mastoiditis in Children Before and After the Introduction of Conjugate Pneumococcal Vaccines.

OBJECTIVES: To determine whether serotype distribution and antibiotic resistance of Streptococcus pneumoniae acute mastoiditis (AM) in children have changed in the post pneumococcal conjugate vaccines (PCVs) era. METHODS: Medical records of pneumococcal AM cases, in a tertiary pediatric hospital were reviewed from January 1999 to December 2014. S. pneumoniae isolates were serotyped using the quellung reaction and tested for antibiotic susceptibility by E-test and for macrolide resistance genes by polymerase chain reaction. RESULTS: Among 334 children with AM, S. pneumoniae was isolated from 89 (26.6%) with median age 22 months (interquartile range: 12-30 months). S. pneumoniae was recovered from ear fluid (58%), mastoid specimens (35.2%) and blood (6.8%). Resistance to penicillin, erythromycin and clindamycin was 12.4%, 49.4% and 18%, respectively. Distribution of pneumococcal serotypes before (1999-2005), after the introduction of PCV7 (2006-2010) and after PCV13 (2011-2014) was found: for the PCV7 serotypes 81%, 25% and 0% (P < 0.0001), for PCV13 additional serotypes 16.3%, 70.8% and 63.6% (P < 0.0001) and for non-PCV serotypes 2.3%, 4.1% and 36.3% (P = 0.0002), respectively. Significant increase was detected for the serotype 19A after PCV7, and this trend was not changed after PCV13 (2.3%, 50% and 50%, respectively; P < 0.0001). A significant proportion of resistant isolates to penicillin (54.5%) and erythromycin (34.8%) was identified as 19A. CONCLUSIONS: After the introduction of PCV7, a significant increase of serotype 19A and replacement of PCVs serotypes was identified. After PCV13, the overall proportion of pneumococcal mastoiditis and the incidence of serotype 19A were not significantly declined. A significant proportion of resistant isolates to penicillin and erythromycin is attributed to serotype 19A.

Rotavirus Gastroenteritis in a Neonatal Unit of a Greek Tertiary Hospital: Clinical Characteristics and Genotypes.

INTRODUCTION: Rotavirus (RV) infection in neonatal age can be mild or even asymptomatic. Several studies have reported that RV is responsible for 31%-87% of pediatric nosocomial diarrhea and causes gastroenteritis outbreaks in pediatric and neonatal units. OBJECTIVES: Study clinical characteristics, genotypes and risk factors of RV infection in neonatal age. METHODS: A prospective study was conducted from April 2009 till April 2013 in the neonatal special care unit of the largest tertiary pediatric hospital of Greece. Fecal samples and epidemiological data were collected from each neonate with gastrointestinal symptoms. RV antigen was detected with a rapid immunochromatography test. RV positive samples were further genotyped with RT PCR and sequencing using specific VP7 and VP4 primers. RESULTS: Positive for RV were 126/415 samples (30.4%). Mean age of onset was 18 days. Seventy four cases (58%) were hospital acquired. Seasonality of RV infection did not differ significantly throughout the year with the exception of 4 outbreaks. Genotypes found during the study period were G4P[8] (58.7%), G1P[8] (14.7%), G12P[8] (9.3%), G3P[8] (9.3%), G12P[6] (5.3%), G9P[8] (1.3%) and G2P[4] (1.3%). RV cases presented with: diarrhea (81%), vomiting (26.2%), fever (34.9%), dehydration (28.6%), feeding intolerance (39.7%), weight loss (54%), whilst 19% of cases were asymptomatic. Comparing community with hospital acquired cases differences in clinical manifestations were found. CONCLUSIONS: Significant incidence of nosocomially transmitted RV infection in neonatal age including asymptomatic illness exists. Genotypes causing nosocomial outbreaks are not different from community strains. Circulating vaccines can be effective in prevention of nosocomial RV infection through herd immunity.

Pasteurella multocida Infection in a neonate: evidence for a human-to-human horizontal transmission.

Pasteurella multocida is usually transmitted by animal contact; however, in a significant proportion of cases, no animal exposure can be identified. Although vertical transmission has been identified in neonates, horizontal human-to-human spread has not been documented. A case of neonatal sepsis and meningitis resulting from horizontal transmission of P. multocida is described.