Occurrence of K1 and K2 serotypes and genotypic characteristics of extended spectrumβ-lactamases-producing Klebsiella pneumoniae isolated from selected hospitals in Malaysia

Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia.Methods:A total of 192 K.pneumoniae isolates were collected and subjected to antibiotic susceptibility,hypermucoviscosity test and multiplex PCR to detect the presence of K1-and K2-serotype associated genes.Multilocus sequence typing(MLST)was performed on ESBL-producing K.pneumoniae isolates presented with K1 and K2 serotypes,followed by phylogenetic analysis.Results:A total of 87 out of 192(45.3%)of the K.pneumoniae isolates collected were ESBL producers.However,only 8.3%(16/192)and 10.9%(21/192)of the total isolates were detected to carry K1-and K2-serotype associated genes,respectively.Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype(P=0.196).However,they were significantly associated with hypervirulent,as demonstrated by the positive string test(P<0.001).MLST analysis revealed that ST23 as the predominant sequence type(ST)in the K1 serotype,while the ST in the K2 serotype is more diverse.Conclusions:Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low,their coexistence warrants the need for continuous surveillance.MLST showed that these isolates were genetically heterogeneous.

Molecular epidemiology of piliated pneumococcal isolates at a major tertiary hospital in the Klang Valley,Malaysia

Objective:To characterise a collection of pili-carrying and none pili-carrying pneumococcal isolates of clinical origin for serotypes,antibiotic resistance and genotype.Methods:In total,42 clinical isolates were collected between October 2017 and December 2019.Those isolates were analysed for antimicrobial susceptibility,serotype distribution,detection of pneumococcal virulence and pilus genes.Multilocus sequence typing was performed only for piliated isolates,followed by phylogenetic analysis.Results:The common isolation sites among the pneumococcal isolates were tracheal aspirate(28.6%),blood(26.2%),and sputum(23.8%).Fifty percent isolates were resistant to erythromycin,tetracycline(50.0%)and trimethoprim-sulfamethoxazole(43.0%).The most frequent were serotypes 19F(28.6%),6A/B(23.8%)and 19A(14.3%).Piliated isolates were detected in a small proportion(33.3%);64.3%were multidrug-resistant.ST320 was the prevalent sequence type among the piliated isolates and genetically related to the Pneumococcal Molecular Epidemiology Network clones Taiwan19F-14(CC271).In the phylogenetic analysis,some piliated isolates showed a close association having similar ST320,carrying serotype 19A and both pilus genes indicating their clonal spread.Conclusions:Pneumococcal lineages of piliated isolates have been globally disseminated and pili could have played a role in the spread of antibiotic resistant clones.

The evolution of pneumococcal vaccine on children in Malaysia:the efficacy and outcome

With pathogenic bacterium,numerous studies have been conducted in developing new vaccines,and available pneumococcal vaccines have been implemented for the prevention of related diseases.Meanwhile,Streptococcus pneumoniae is known to have developed resistance to many of the proposed preventive measures.As a result,contemporary research,including our study,has reviewed how Streptococcus pneumoniae has become resistant to vaccines and to further determine how to prevent the negative effect of the non-vaccine serotype on vaccine serotype efficacy.Pneumococcal have been known as one of the bacteria that has highest preventive strength of vaccination provided to humans,where children’s immunity requires the vital of it,based on immunization schedule to boost their immune system against the diseases of high mortality and morbidity.All pneumococcal vaccines are derived from its strains called serotypes,and further research is being conducted to determine more potent vaccines from other pneumococcal virulence factors.To impose and implement the pneumococcal vaccine,the serotype distribution needs to be verified.To deal with this verification,clinical or carriage samples are required for the determination and differentiation of vaccine serotypes from non-vaccine serotypes.In Malaysia,the carriage rates are often limited to the clinical epidemiology of Streptococcus pneumoniae.Carriage samples are more needed in tracking the vaccine efficacy for pre-and post-immunization to prevent and reduce pneumococcal diseases before they manifest into clinical infections.Thus,in this review article,we explore the mentioned highlights for sufficient discussion,discovery,and knowledgeable implementation of pneumococcal vaccine.