Serotypes & penicillin susceptibility of Streptococcus pneumoniae isolated from children admitted to a tertiary teaching hospital in Malaysia

Background & objectives: Streptococcus pneumoniae (pneumococcus) is a highly invasive extracellular pathogen that causes diseases such as pneumonia, otitis media and meningitis. This study was undertaken to determine the serotype diversity and penicillin susceptibility of S. pneumoniae isolated from paediatric patients in a tertiary teaching hospital in Malaysia. Methods: A total of 125 clinical isolates collected from January 2013 to May 2015 were serotyped using seven sequential multiplex polymerase chain reactions. The susceptibility of these isolates to penicillin was also investigated. Results: Serotypes detected among the isolates were serotypes 3, 6A/B, 6C, 11/A/D/F, 15A/F, 19A, 19F, 23A, 23F, 34. Serotypes 19F and 6A/B were the most prevalent serotypes detected. Most of the S. pneumoniae were isolated from nasopharyngeal samples of children below five years of age. Majority of the isolates were penicillin susceptible. Only 5.6 per cent of the isolates were non-susceptible to penicillin, mostly of serotype 19F. Interpretation & conclusions: Our study revealed the distribution of various serotypes in S. pneumoniae isolates obtained from children in a teaching hospital at Kuala Lumpur, Malaysia and decreasing rates of penicillin resistance among them. The shifts in serotypes and susceptibility to penicillin from time to time have been observed. Continuous monitoring and surveillance are pivotal for better infection control and management of pneumococcal infections among children.

Molecular epidemiology of Streptococcus agalactiae isolated from mastitis in Brazilian dairy herds

Abstract Streptococcus agalactiae is one of the most common pathogens leading to mastitis in dairy herds worldwide; consequently, the pathogen causes major economic losses for affected farmers. In this study, multilocus sequence typing (MLST), genotypic capsular typing by multiplex polymerase chain reaction (PCR), and virulence gene detection were performed to address the molecular epidemiology of 59 bovine (mastitis) S. agalactiae isolates from 36 dairy farms located in the largest milk-producing mesoregions in Brazil (Minas Gerais, São Paulo, Paraná, and Pernambuco). We screened for the virulence genes bac, bca, bibA, cfb, hylB, fbsA, fbsB, PI-1, PI-2a, and PI-2b, which are associated with adhesion, invasion, tissue damage, and/or immune evasion. Furthermore, five capsular types were identified (Ia, Ib, II, III, and IV), and a few isolates were classified as non-typeable (NT). MLST revealed the following eight sequence types (STs): ST-61, ST-67, ST-103, ST-146, ST-226, ST-314, and ST-570, which were clustered in five clonal complexes (CC64, CC67, CC103, CC17, and CC314), and one singleton, ST-91. Among the virulence genes screened in this study, PI-2b, fbsB, cfb, and hylB appear to be the most important during mastitis development in cattle. Collectively, these results establish the molecular epidemiology of S. agalactiae isolated from cows in Brazilian herds. We believe that the data presented here provide a foundation for future research aimed at developing and implementing new preventative and treatment options for mastitis caused by S. agalactiae.

Prospective epidemiological study on the adults of lower respiratory tract infection with haemophilus influenzae in Chengdu area / 中华检验医学杂志

Objective To investigate the epidemic strains of biological type, drug resistance, and the basic clinical characteristics of haemophilus influenzae(Hi)isolated from hospitalized adults with lower respiratory tract infection in Chengdu area.Methods A prospective cross-sectional study was conducted to analyze the biological typing,capsular genes detected by PCR technique,and drug resistance tested by drug sensitive test of Hi epidemic strains isolated from the sputum of adults aged above 18 years who were hospitalized in two tertiary hospitals of west Sichuan in China.Results The positive rate of pathogenic bacteria in adults aged above 18 years who were hospitalized in the two hospitals was 46.71%(15 447/33 069)between November 2013 and October 2014.The positive rate of Hi isolated from the sputum of 100 adults with lower respiratory tract infection was 0.31%(101/33 069).The constituent ratio of Hi in lower respiratory tract infection pathogens was 0.65%(101/15 447).The Hi were all undifferentiated type detected by PCR,and the biological typing of Hi were typeⅠ(42.57%),Ⅳ(29.7%),Ⅱ(15.84%),Ⅲ(9.9%),Ⅶ(1.98%), and Ⅵ(0.9%).The diseases of Hi positive were acute phase of chronic obstructive pulmonary disease(59%), pneumonia(35%), and bronchitis(6%), in which community acquired infection was 55%.The rate of β-lactamase enzyme production was 38.61%.The frequencice of β-lactamase -nonproducing-ampicillin-resistant(BLNAR)strains was 2.97%,and of intermediary strains was 4.95%(5/101).The drug resistance rate of amoxicillin and clavulafiate was 2.97%.The drug resistance rate of cefuroxime was 12.87%, and intermediary rate was 12.87%.The drug resistance rate of cefaclor was 29.7%,and intermediary rate was 8.91%.The drug resistance rate of cefotaxime and ofloxacin was 6.93%and 1.99%.There were no obvious statistical differences between the drug resistance rates of the two hospitals.Conclusions The Hi epidemic strains isolated from the sputum of adults with lower respiratory tract infection were all undifferentiated type,and the common biological types were Ⅰ,Ⅳ,Ⅱ, andⅢ in west Sichuan in China.It should pay attention to the BLNAR strains and ofloxacin-resistant strains.

Tipificación capsular mediante PCR de aislamientos de Haemophilus influenzae no tipificables por aglutinación / PCR-based capsular typing of Haemophilus influenzae isolates non-typeable by agglutination

Haemophilus influenzae es reconocido como un agente patógeno responsable de infecciones localizadas y sistémicas. Se han descrito 6 tipos de polisacáridos capsulares antigénicamente distintos (a, b, c, d, e, y f ) que se pueden identificar por aglutinación en lámina con antisueros específicos. También existen cepas no capsuladas (NC) fenotípicamente no tipificables (NT). La introducción de la vacuna conjugada produjo una marcada disminución de las enfermedades invasivas causadas por H. influenzae tipo b. En este contexto, la tipificación capsular mediante PCR es el método más apropiado para distinguir las cepas no capsuladas de las mutantes b deficientes en cápsula (b-) y detectar la presencia de cepas pertenecientes a otros serotipos que no puedan ser tipificables por aglutinación. Se determinó el genotipo capsular a 38 aislamientos de Haemophilus influenzae no tipificables por aglutinación, derivados al servicio de Bacteriología Clínica del INEI-ANLIS "Dr. Carlos G. Malbrán" en el período 2002-2004. El 78,9% de los aislamientos provenían de hemocultivos y la mayor parte de ellos estaban asociados a foco respiratorio. El 100% de los aislamientos fueron identificados como H. influenzae no capsulados mediante la técnica de PCR.

Haemophilus influenzae is recognized as a pathogenic agent responsible of localized and systemic infections. Six antigenically different capsular polysaccharide types have been described (a, b, c, d, e, and f ) which can be identified by slide agglutination with specific antisera. Besides there are non capsulated strains that cannot be typed by slide agglutination. The introduction of the conjugated vaccine produced an important reduction of invasive diseases caused by H. influenzae type b. Capsular typing by PCR is the most appropriated method for distinguishing non capsulated strains from capsule deficient type b mutants (b-) and for detecting strains of other serotypes that cannot be detected by slide agglutination. Capsular genotype was studied in 38 isolates of non-typeable Haemophilus influenzae received at INEIANLIS "Dr. Carlos G. Malbrán" between 2002-2004. Of the isolates included in this study 78.9% of them were recovered from blood cultures and most of them were associated with a respiratory focus. By PCR technique 100% of the isolates were identified as non-capsulate H. influenzae and genotype b-was not detected.