Structure of Pneumococcal Bacteria

Early observations by application of specific strains revealed that virulent pneumococci were surrounded by a structure now recognized as the capsule. The capsule played a central role in the discovery of the ‘transforming principle’ since it was using this genetic trait and this microorganism where DNA and genetic information were first linked. (R. Lopez et al., 2004) As in other Gram positive bacteria, the pneumococcal cell wall is composed of peptidoglycan and teichoic acid. A predominant component of teichoic acid is the C-polysaccharide which is covalently bound to the peptidoglycan layer and distributed both on its inner and outer side. (M. Kalin et al.,)

More recently, it has been proposed to develop substances that specifically inhibit bacterial virulence such as ‘‘antipathogenic’’ drugs, in contrast to antibacterial drugs, do not kill bacteria or stop their growth and are assumed not to lead to the development of resistant strains.(M. Otto et al., 2004) The pneumococcal polysaccharide capsule is crucial for virulence, primarily by protecting the bacteria against phagocytosis. Capsular gene cassette transformation, leading to a change in the capsule specificity, is a common event in such antibiotic resistant clones, and possibly also in more natural clones. (M. Kalin et al.,)Streptococcus pneumoniae (pneumococcus) remains the leading cause of community-acquired pneumonia, meningitis, and bacteremia in children and adults, and the most common cause of otitis media in infants and young children (Lynch JP et al., 2015).

Globally, pneumonia remains the most common cause of death in children younger than 5 years of age, causing 1.6 million deaths annually, Black RE (2015). Despite routine microbiological testing, the microbial etiology of CAP is not always identified, but with current laboratory investigations a diagnosis usually can be made in up to 60% of patients (C. Feldman et al., 2014).The first report regarding the emergence of fluoroquinolone resistance among S. pneumoniae isolates in Asia was from Hong Kong, and a subsequent case-control study showed that the presence of chronic obstructive pulmonary disease, nosocomial origin of the bacteria, residence in a nursing home, and exposure to fluoroquinolones were independently associated with levofloxacin-resistant S. pneumoniaecolonization or infection].

In a Taiwanese hospital, rates of levofloxacin nonsusceptibility of S. pneumoniae increased significantly from 1.2% in 2001 to 4.2% in 2007 The ANSORP study showed that the resistance rates to fluoroquinolones were 1.7%, 0.4%, 1.5%, and 13.4% for levofloxacin, moxifloxacin, gatifloxacin, and ciprofloxacin, respectively, in Asian countries. Isolates from Taiwan (6.5%) and South Korea (4.6%) showed the highest rates of levofloxacin resistance a case of bacteremic pneumonia caused by an extremely drug-resistant strain of S. pneumoniae, nonsusceptible to at least one agent in all classes but vancomycin and linezolid, was reported in Korea (jae- hoon – song et aL 2013)

The impact of antibiotic-resistant pneumococcus has not been evaluated and is likely to depend upon many factors including whether antibiotic treatment is consistent or non consistent with the susceptibility profile of the infecting strain. Discordant treatment may result in delayed cure, multiple outpatient visits or hospitalization, and increases in morbidity, mortality and cost (Reynolds et al., 2014).Analysis of capsule switch constructs showed that strain to strain differences in survival were due to capsule type rather than genetic background. The addition of glucose was sufficient to rescue the survival defect of the capsule deficient derivative demonstrating that in the absence of capsule survival depends upon nutrient availability. (Shigeto Hamaguchi et al., 2018).

Pneumococci are enclosed in a complex polysaccharide capsule that determines the serotype; the capsule varies in size and also associated with the properties that includes carriage prevalence and virulence. determined and quantified the association between capsule and recombination events using a genomic data (Chrispin Chaguza, et al., 2016)The levels of antimicrobial resistance of S. pneumoniae isolates in many

Asian countries are among the highest in the world during the early part of this century. Isolates from Vietnam showed the highest prevalence of penicillin resistance at 71.4%;and erythromycin resistance at 92.1%. Isolates from Hong Kong showed the highest rate of ciprofloxacin resistance at 11.8%. Resistance to penicillin ranged from 38.6% among isolates from Taiwan to 71.4% among isolates from Vietnam. Erythromycin resistance was from 73.9% (China) to 92.1 % (Vietnam) while resistance to ciprofloxacin was from 6.5% (Korea) to 11.8% (Hong Kong). Data from the Philippines showed that 18.2% of the isolates were resistant to erythromycin while 9.1% were ciprofloxacin resistant. Statistics from the Philippines’ Antimicrobial Resistance Surveillance Program (ARSP) progress reports also showed resistance rates of pneumococci to cotrimoxazole to be higher (from 14% in 2006 to 15% in 2011) relative to other antibiotics.