Presence of international multiresistant clones of Streptococcus pneumoniae in Colombia

Sentinel surveillance for bacterial pneumonia and meningitis in children under the age of 5 in a tertiary pediatric hospital in Colombia - 2016

Introduction:

Bacterial pneumonia and meningitis are vaccine-preventable diseases. Sentinel surveillance provides relevant information about their behavior.

Objective:

To present the data from sentinel surveillance carried out at the Fundación HOMI, Fundación Hospital Pediátrico La Misericordia in 2016.

Materials and methods:

We conducted a descriptive study from January 1 to December 31, 2016, on the daily surveillance of patients under 5 years of age diagnosed with pneumonia or bacterial meningitis according to PAHO's definitions. We identified the microorganisms using the automated VITEK^TM 2 system. Bacterial isolates were sent to the Microbiology Group at the Colombian Instituto Nacional de Salud for confirmation, serotyping, phenotypic, and genotypic characterization. Antimicrobial susceptibility profiles were established.

Results:

From 1,343 suspected cases of bacterial pneumonia, 654 (48.7%) were probable, 84% had complete Hib vaccination schedules, and 87% had complete pneumococcal vaccination schedules for age. Blood culture was taken in 619 (94.6%) and 41 (6.6%) were positive while S. pneumoniae was isolated in 17 (41%) of them. The most frequent serotype was 19A in five cases (29.4%), and four 19A serotypes were associated with the reference isolate ST320. The incidence rate of probable bacterial pneumonia was 7.3 cases/100 hospitalized patients, and lethality was 2.1%. As for bacterial meningitis, 22 suspected cases were reported, 12 (54%) were probable, four (33%) were confirmed: two by Escherichia coli and two by group C N. meningitidis. The incidence of probable bacterial meningitis was 0.14 cases/100 hospitalized patients.

Conclusion:

Streptococcus pneumoniae serotypes 19A and 3 were the most frequent cause of pneumonia. Spn19A is related to the multi-resistant clone ST320. Strengthening and continuing this strategy will allow understanding the impact of vaccination.

Streptococcus pneumoniae serotype 3 genotypes in invasive isolates from Colombia

Introduction:

Streptococcus pneumoniae serotype 3 is an important cause of pneumonia, bacteremia, and meningitis.

Objective:

To establish the circulating genotypes of S. pneumoniae serotype 3 isolates recovered from the invasive disease between 1994 to 2015 in Colombia.

Materials and methods:

Of the 365 S. pneumoniae serotype 3 isolates recovered through the laboratory national surveillance program, 117 isolates were analyzed. Pulsed-field gel electrophoresis was used for genotyping, and multilocus sequence typing was determined in representative isolates.

Results:

The frequency of this serotype increased from 2.7% between 1994 and 1998 to 9.1% between 2011 and 2015 (p=0.000); 91.7% of the isolates showed a genetic similarity greater than 77% and were related to the Netherlands³-31(PMEN31) clone CC180. Several subtypes were identified, two of which showed antimicrobial resistance.

Conclusion:

In Colombia, the pneumococcal population of the capsular type 3 shows a continuous and homogeneous circulation relating to the clonal group ST-180.

Molecular characterization of Latin American invasive Streptococcus pneumoniae serotype 19A isolates

Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide, especially among children and the elderly. S. pneumoniae serotype 19A has emerged as a major cause of invasive disease in many countries, regardless of whether pneumococcal conjugate vaccines are used. The aim of this study was molecular characterization of invasive S. pneumoniae serotype 19A isolates recovered between 2000 and 2015 from 13 National Laboratories through the laboratory-based surveillance of invasive S. pneumoniae program SIREVA II in Latin American countries. The isolates were submitted with antimicrobial susceptibility tests and were genotyped by a combination of pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Of the 185 isolates assayed, notable rates of resistance to penicillin (MIC ≥ 0.125 µg/mL; 68.6%), tetracycline (63.7%), trimethoprim-sulfamethoxazole (63.2%), and erythromycin (43.2%) were observed, while 44.3% of isolates were multidrug resistant. The most frequently observed sequence types (ST) were ST320 (32.4%), ST199 (14.1%), ST172 (10.8%) and ST5204 (7.1%). The distribution of STs indicated regional differences in the epidemiology of the clonal groups. The present study showed a diverse genetic background of the pneumococcal population in Latin American countries. Continuous surveillance of the pneumococcal serotype 19A population in the region will be necessary to obtain information about geographical differences and changes in the spread and the establishment of particular clones.

Molecular characterization of non-vaccine Streptococcus pneumoniae serotypes 11A, 15 B/C and 23A recovered from invasive isolates in Colombia

Introducción. En Colombia se recolectaron 192 aislamientos invasivos de Streptococcus pneumoniae de los serotipos 11A, 15B/C y 23A (no incluidos en las vacunas conjugadas) entre 1994 y 2014, como parte de las actividades del Sistema de Redes de Vigilancia de los Agentes Responsables de Neumonías y Meningitis Bacterianas (SIREVA II).Objetivo. Determinar las características moleculares de aislamientos invasivos de los serotipos 11A, 15B/C y 23A de S. pneumoniae recolectados en Colombia entre 1994 y 2014. Materiales y métodos. La caracterización molecular de los aislamientos se hizo mediante electroforesis en gel de campo pulsado (Pulse-Field Gel Electrophoresis, PFGE) y por tipificación de secuencias multilocus (Multilocus Sequence Typing, MLST).Resultados. El serotipo 11A mostró un grupo clonal representado por el ST62, en tanto que el serotipo 15B/C se distribuyó en tres grupos asociados con los clones Netherlands15B-37 ST199 (28,75 %), ST8495 (18,75 %) y SLV (variante en un solo locus) de ST193 (21,25 %). Los aislamientos con serotipo 23A se agruparon en tres grupos clonales; 70,21 % de ellos estaban estrechamente relacionados con el ST42, 17,02 % con el Colombia23F-ST338, y 6,38 % con el Netherlands15B-37 ST199.Conclusión. Los clones Colombia23F-ST338 y Netherlands15B-ST199 encontrados en este estudio abarcaron más serotipos de los reportados previamente por otros autores, incluido el serotipo 23A. Estos análisis revelan la importancia de la conmutación (switching) capsular en la expansión de clones exitosos entre los serotipos no vacunales como causa de enfermedad invasiva neumocócica.

Serotype and genotype distribution among invasive Streptococcus pneumoniae isolates in Colombia, 2005-2010

In Colombia, a laboratory-based surveillance of invasive Streptococcus pneumoniae isolates as part of SIREVA II PAHO has been conducted since 1994. This study describes the serotype distribution, antimicrobial resistance, and genetic relationships of pneumococcal isolates recovered in Colombia from 2005 to 2010. In this study, demographic data of invasive S. pneumoniae isolates were analyzed, and antimicrobial susceptibility patterns were determined. Pulse field gel electrophoresis (n = 629) and multilocus sequence typing (n = 10) were used to determine genetic relationship of isolates with minimal inhibitory concentration to penicillin ≥0.125 µg/mL. A total of 1775 isolates of S. pneumoniae were obtained. Fifteen serotypes accounted for 80.7% of isolates. Serotype 14 (23.1%) was the most frequent in the general population. Penicillin resistance was 30.7% in meningitis and 9.0% in non-meningitis. Clones Spain^6BST90, Spain^9VST156, Spain^23FST81, and Colombia^23FST338 were associated to isolates. Additionally, serotype 6A isolates were associated with ST460 and ST473, and 19A isolates with ST276, ST320, and ST1118. In conclusion, the surveillance program provided updated information of trends in serotype distribution, antimicrobial resistance and the circulation of clones in invasive pneumococcal diseases. These results could be helpful to understand the epidemiology of S. pneumoniae in Colombia, and provide a baseline to measure the impact of vaccine introduction.

Characterization of Streptococcus pneumoniae invasive serotype 19A isolates recovered in Colombia

The aim of this study was to determine the molecular characterization of invasive penicillin non-susceptible Streptococcus pneumoniae serotype 19A isolates, collected in Colombia between 1994 and 2012. A total of 115 isolates serotype 19A were analyzed. Genetic relationship of 80 isolates with minimal inhibitory concentration (MIC) to penicillin ≥0.125 μg/was determined by pulsed-field gel electrophoresis (PFGE) and selected strains were studied by multilocus sequence typing (MLST). Among the 115 isolates, resistance to penicillin in meningitis was 64.2%, in non-meningitis 32.2% were intermediate and 1.1% were high resistance. The most frequent sequence types were ST320 (33.7%), ST276 (21.5%), and ST1118 (11.2%). Five isolates were associated with the Spain(9V)-ST156 clone, and two isolates were related to Colombia(23F)-ST338 clone. S. pneumoniae serotype 19A increased in Colombia was associated with the spread of isolates genetically related to ST320 and ST276, and emergence of capsular variants of worldwide-disseminated clones.

Characterization of macrolide resistance in Gram-positive cocci from Colombian hospitals: a countrywide surveillance

OBJECTIVE

The characterization of macrolide resistance in Gram-positive cocci recovered from Colombian hospitals.

METHODS

The resistance profiles and mechanism of macrolide resistance were investigated in isolates of Streptococcus pneumoniae (1679), Staphylococcus aureus (348), coagulase-negative staphylococci (CoNS) (175), and Enterococcus spp (123). Minimum inhibitory concentrations (MICs) for erythromycin (ERY) and clindamycin (CLI), detection of macrolide resistance genes, phenotypic characterization, and pulsed field gel electrophoresis (PFGE) of macrolide-resistant pneumococci were performed.

RESULTS

Resistance to ERY and CLI was 3.3% and 2.3% for S. pneumoniae, 58% and 57% for S. aureus (94% for both compounds in methicillin-resistant Staphylococcus aureus (MRSA)), and 78.6% and 60.7% in methicillin-resistant Staphylococcus epidermidis, respectively. ERY resistance was 62% in Enterococcus faecalis and 82% in Enterococcus faecium. The MLS(B)-type accounted for 71% of S. pneumoniae and 100% of MRSA. The erm(A) gene was prevalent in MRSA, erm(B) in S. pneumoniae and enterococci, and erm(C) in CoNS isolates. Efflux pump genes (mef(A) genes) were mostly identified in S. pneumoniae (24%). The most common genotype amongst ERY-resistant pneumococci was the Spain(6B)-2 clone.

CONCLUSIONS

The prevalence of macrolide resistance is low in Colombian pneumococci and high in MRSA (cMLS(B)-type).

Dissemination of Streptococcus pneumoniae clone Colombia(5)-19 in Latin America

Streptococcus pneumoniae serotype 5 is the third most common capsular type causing invasive diseases in children younger than 5 years in Latin America. Preliminary data on Colombian serotype 5 isolates indicated a common clonal origin associated with resistance to tetracycline (TET) and chloramphenicol (CHL). We studied 172 S. pneumoniae serotype 5 invasive isolates from Argentina, Brazil, Colombia, Guatemala, Mexico, and Uruguay and confirmed the presence of the Colombia(5)-19 clone throughout Latin America. Fifteen subtypes of a pulsed-field gel electrophoresis pattern and 4 electrophoretic types (ET) were obtained. Most of the isolates from different geographical regions belonged to pattern A (34.3%), subtype A5 (41.9%), and ET1 (91.1%). The A pattern (n = 59) was resistant to TET and had variable resistance to CHL; it was present in Brazil (10.2%), Colombia (78%), Guatemala (8.5%), and Mexico (3.4%). Subtype A5 with variable susceptibility to TET and sensitive to CHL was found in Argentina (29.2%), Mexico (8.3%), and Uruguay (62.5%). Subtypes A1-A4, A7-A8, and A9-A11 (closely related to A) also shared ET1, while subtype A6 was assigned to ET1, ET2, and ET3. Eleven subtypes (n = 21) were found to be specific for one country each. In summary, the S. pneumoniae serotype 5 isolates from Latin American are genetically closely related but show different patterns of antibiotic resistance, probably as a result of horizontal transfer.

First characterization of a cluster of VanA-type glycopeptide-resistant Enterococcus faecium, Colombia

From August 1998 to October 1999, glycopeptide-resistant enterococci (GRE) were isolated from 23 infected patients at a teaching hospital in Medellín, Colombia. Identification at the species level and by multiplex polymerase chain reaction assay indicated that all isolates were Enterococcus faecium. The isolates were highly resistant to ampicillin, ciprofloxacin, gentamicin, penicillin, streptomycin, teicoplanin, and vancomycin; they were susceptible only to chloramphenicol, linezolid, and nitrofurantoin. Determination of glycopeptide genotype indicated the presence of the vanA gene in all isolates. Molecular typing by pulsed field gel electrophoresis showed that all isolates were closely related. This study is the first molecular characterization of GRE in Colombia.

Pneumococcal surface protein A of invasive Streptococcus pneumoniae isolates from Colombian children

Pneumococcal surface protein A (PspA) elicits protection in mice against fatal bacteremia and sepsis caused by genetically diverse pneumococci and protects against carriage and lung infection. We determined the PspA families of invasive isolates of Streptococcus pneumoniae recovered from Colombian children <5 years of age. That 97.5% of Colombian isolates belong to PspA families 1 and 2 supports the hypothesis that a human PspA vaccine covering a few PspA families could be broadly effective.