Serotypes and antibiotic resistance of non-invasive Streptococcus pneumoniae circulating in pediatric hospitals in Moscow, Russia.
BACKGROUND
Pneumococcal infections remain a major medical problem associated with high morbidity and mortality. Moreover, the resistance of Streptococcus pneumoniae to conventional antibiotics is constantly growing. The implementation of pneumococcal conjugate vaccines (PCVs) in the last decade has dramatically reduced the incidence of the vaccine type-associated invasive pneumococcal diseases in many countries. However, information on the seroepidemiology of S. pneumoniae in Russia is limited.


METHODS
We report the results of serotyping and antibiotic susceptibility testing performed on 863 non-invasive pneumococcal isolates collected prospectively in 2009-2013 from children (median age 3.5 years) who sought medical care at five pediatric hospitals in Moscow. The isolates were recovered from the nasopharynx (71.2%), middle ear fluid (14.3%), and lower respiratory tract specimens (13.6%).


RESULTS
In total, we identified 45 different serotypes. The six leading serotypes (prevalence >5%) included 19F (21.7%), 6B (12.8%), 23F (10.1%), 14 (9.0%), 6A (8.4%), and 3 (7.5%). Serotype 19A isolates had a prevalence of 2.3%. The proportion of PCV-13 serotypes was 78%; the coverage by PCV-7 was 58.2% and was similar to that of PCV-10 (59.8%). The rate of multidrug-resistant pneumococci (i.e., resistant to ≥3 antimicrobials) was 22%. The majority of the multidrug-resistant isolates were serotype 6B, 14, 19A, and 19F. Penicillin non-susceptibility was displayed by 28% of the isolates. The resistance rate to erythromycin was 26%. Among the examined erythromycin-resistant strains, 54% had the erm(B) gene and 13% had the mef gene as a single resistance determinant, whereas both determinants were found in 31% of these strains.


CONCLUSIONS
Our data predict a good coverage of the circulating S. pneumoniae by the PCVs and could be useful for evaluating the serotype distribution in support of the introduction of PCV in Russia. In addition, the antimicrobial resistance rate of S. pneumoniae in Russia is substantial, and the emergence of pneumococcal strains with a dual macrolide resistance mechanism is alarming.
Scientific Center for Children's Health, 119991, Lomonosovskiy Avenue, 2, Moscow, Russia. Electronic address: mayansky@nczd.ru.
Nikolay
N
Mayanskiy
Scientific Center for Children's Health, 119991, Lomonosovskiy Avenue, 2, Moscow, Russia.
Natalia
N
Alyabieva
Scientific Center for Children's Health, 119991, Lomonosovskiy Avenue, 2, Moscow, Russia.
Olga
O
Ponomarenko
Scientific Center for Children's Health, 119991, Lomonosovskiy Avenue, 2, Moscow, Russia.
Anna
A
Lazareva
Scientific Center for Children's Health, 119991, Lomonosovskiy Avenue, 2, Moscow, Russia.
Lubovj
L
Katosova
Morozovskaya Children's Hospital, Moscow, Russia.
Alexander
A
Ivanenko
Scientific Center for Children's Health, 119991, Lomonosovskiy Avenue, 2, Moscow, Russia.
Tatiana
T
Kulichenko
Scientific Center for Children's Health, 119991, Lomonosovskiy Avenue, 2, Moscow, Russia.
Leila
L
Namazova-Baranova
Scientific Center for Children's Health, 119991, Lomonosovskiy Avenue, 2, Moscow, Russia.
Alexander
A
Baranov
D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D004917:Erythromycin / Q000627:therapeutic use; D006776:Hospitals, Pediatric; D006801:Humans; D015994:Incidence; D018942:Macrolides; D009031:Moscow / Q000453:epidemiology; D009305:Nasopharynx / Q000382:microbiology; D010406:Penicillins / Q000627:therapeutic use; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D011446:Prospective Studies; D016036:Seroepidemiologic Studies; D012703:Serotyping; D013048:Specimen Handling; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification*; D018074:Vaccines, Conjugate / Q000627:therapeutic use
D018942:Macrolides; D010406:Penicillins; D018074:Vaccines, Conjugate; D004917:Erythromycin
Antibiotic resistance; Children; Pneumococcal conjugate vaccine; Serotype; Streptococcus pneumoniae