Low incidence of antibiotic resistance among invasive and nasopharyngeal isolates of Streptococcus pneumoniae from children in rural Philippines between 1994 and 2000

Systematic review of the clinical outcomes of pneumonia with a penicillin-group resistant pneumococcus in respiratory and blood culture specimens in children in low- and middle-income countries

Background

Streptococcus pneumoniae is one of the most common bacteria causing pneumonia and the World Health Organization (WHO) recommends first-line treatment of pneumonia with penicillins. Due to increases in the frequency of penicillin resistance, this systematic review aimed to determine the clinical outcomes of children with pneumonia in low- and middle-income countries (LMICs), with penicillin-group resistant pneumococci in respiratory and/or blood cultures specimens.

Methods

English-language articles from January 2000 to November 2020 were identified by searching four databases. Systematic reviews and epidemiological studies from LMICs that included children aged one month to 9 years and reported outcomes of pneumonia with a penicillin-resistant pneumococcus in respiratory and blood culture specimens with or without comparison groups were included. Risk of bias was assessed using the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies. A narrative synthesis of findings based on the results of included studies was performed.

Results

We included 7 articles involving 2864 children. One strong- and four medium-quality studies showed no difference in clinical outcomes (duration of symptoms, length of hospital stay and mortality) between those children with penicillin non-susceptible compared to susceptible pneumococci. Two weak quality studies suggested better outcomes in the penicillin-susceptible group.

Conclusions

Current evidence suggests no difference in clinical outcomes of child pneumonia due to a penicillin-resistant S. pneumoniae and as such, there is no evidence to support a change in current WHO antibiotic guidelines.

A Narrative Review of Pneumococcal Disease in Children in the Philippines

This narrative review describes the epidemiology of invasive pneumococcal diseases, nasopharyngeal carriage, and antibiotic resistance of Streptococcus pneumoniae serotypes, and vaccination coverage in children in the Philippines. Epidemiological data show that, despite the availability of the free-of-cost 13-valent pneumococcal conjugate vaccine for infants as part of the National Immunization Program, the burden of pneumococcal disease in young children remains high in the Philippines. The significant variability in data reported between studies highlights an urgent need for active and comprehensive disease surveillance for more accurate estimates of pneumococcal disease in the country. Although data from 2001 to 2013 show high rates of pneumococcal carriage in children in the Philippines aged < 5 years, contemporary data are lacking, again emphasizing the need for active surveillance programs. The introduction of pneumococcal conjugate vaccines has resulted in substantial declines in disease caused by pneumococcal serotypes included in the vaccines, but the emergence of pneumococcal disease due to nonvaccine serotypes is an ongoing concern. Surveillance of actively circulating serotypes is critical to better understand vaccine coverage. Antimicrobial resistance of S. pneumoniae remains a significant threat to public health worldwide; data regarding antibiotic resistance in young children in the Philippines are limited, but reports generally show low rates of antibiotic resistance in this group. National immunization rates have increased in recent years, yet many individuals are still unprotected from pneumococcal disease. Overall, there is a critical need for contemporary and accurate disease surveillance in the Philippines. Such data would provide better estimates of pneumococcal disease incidence, serotype distribution, and antibiotic resistance to better inform vaccination strategies and to ensure that children in the Philippines are best protected against pneumococcal disease.

Colonization dynamics of Streptococcus pneumoniae in a remote African population: A prospective cohort study

The aim of this study was to analyze the population dynamics of Streptococcus pneumoniae in a remotely living African Pygmy population. The same pygmy population (Gabon) was prospectively screened for nasopharyngeal S. pneumoniae colonization in 2011 (n = 103), 2013 (n = 104) and 2017 (n = 107). Non-duplicate isolates (n = 126) were serotyped and tested for antimicrobial resistance (broth microdilution). At the three sampling time points, resistance rates were highest for tetracycline (36-58%), followed by penicillin (parenteral, meningitis-breakpoints, 6-39%) and chloramphenicol (3-15%). The majority of isolates was non-typeable (NT, n = 18/126, 14.3%) followed by serotype 6B (n = 17/126, 13.5%), 21 and 15A (n = 9/126, 7.1%, each). The distribution of serotypes was highly dynamic as only three serotypes (14, 17F, NT) were detected during all three visits. Resistance rates and serotypes of nasopharyngeal S. pneumoniae markedly changed in the remote Babongo population. This rapid change in serotypes could challenge the selection of pneumococcal vaccine.

Community-Acquired Pneumonia in the Asia-Pacific Region

Community-acquired pneumonia (CAP) is an important cause of mortality and morbidity worldwide. Aging population, dense urbanization, and poor access to health care make the Asia-Pacific region vulnerable to CAP. The high incidence of CAP poses a significant health and economic burden in this region. Common etiologic agents in other global regions including Streptococcus pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydophila pneumoniae, Staphylococcus aureus, and respiratory viruses are also the most prevalent pathogens in the Asia-Pacific region. But the higher incidence of Klebsiella pneumoniae and the presence of Burkholderia pseudomallei are unique to the region. The high prevalence of antimicrobial resistance in S. pneumoniae and M. pneumoniae has been raising the need for more prudent use of antibiotics. Emergence and spread of community-acquired methicillin-resistant S. aureus deserve attention, while the risk has not reached significant level yet in cases of CAP. Given a clinical and socioeconomic importance of CAP, further effort to better understand the epidemiology and impact of CAP is warranted in the Asia-Pacific region.

Prospective surveillance study of invasive pneumococcal disease among urban children in the Philippines

BACKGROUND

Worldwide, invasive pneumococcal disease (IPD) causes considerable morbidity and mortality among children, but incidence data in Asia are lacking. This 2-year hospital-based, prospective, surveillance study was conducted at 3 study sites in urban areas of the Philippines to estimate IPD and pneumonia incidence in children and describe the serotype distribution of invasive Streptococcus pneumoniae isolates.

METHODS

Children aged 28 days to <60 months residing within the 3 surveillance areas presenting with possible IPD were enrolled. Initial diagnosis, history of pneumococcal vaccine receipt and previous antimicrobial treatment were recorded. Blood specimens were collected for S. pneumoniae identification and serotyping. Final diagnosis was determined for hospitalized subjects, subjects whose culture yielded S. pneumoniae and subjects with clinically suspected meningitis.

RESULTS

A total of 5940 subjects were enrolled, 47 IPD cases identified. IPD site rates were 33.49 per 100,000, 25.38 per 100,000 and 25.85 per 100,000. Chest radiograph-confirmed pneumonia incidence ranged from 633.74 to 1683.59 per 100,000. Highest chest radiograph-confirmed pneumonia incidence occurred in those 28 days to <6 months of age at 2 sites (2166.16 and 3891.94 per 100,000) and those 6-12 months of age at the third site (3847.52 per 100,000). Thirty-five S. pneumoniae isolates were serotyped; most commonly identified were serotypes 1, 2, 5, 6B, 14 and 18F. One serotype 14 isolate was erythromycin resistant. Previous antibiotic therapy was documented in 17-53% of subjects; 2 subjects had received pneumococcal vaccine. At 2 sites, one-third of IPD subjects died.

CONCLUSIONS

IPD is an important cause of morbidity and mortality among urban children in the Philippines. Our data support the expectation that widespread immunization would decrease IPD disease burden.

Respiratory viruses from hospitalized children with severe pneumonia in the Philippines

BACKGROUND

Pneumonia remains a leading cause of child death in developing countries. The viruses in severe pneumonia remain poorly defined.

METHODS

The study was conducted at the Eastern Visayas Regional Medical Center in Tacloban City, Philippines from May 2008 to May 2009. Patients aged 8 days to 13 years old who were admitted to the Department of Pediatrics with severe pneumonia were enrolled for the study. Upon admission, polymerase chain reaction was performed using nasopharyngeal swabs and blood cultures to detect respiratory viruses and bacteria, respectively.

RESULT

Among the 819 patients enrolled, at least one virus was detected in 501 cases (61.2%). In addition, 423 cases were positive for a single virus while bacteria were detected in the blood culture sample of 31 cases. The most commonly detected viruses were human rhinoviruses (n = 189), including types A (n = 103), B (n = 17), and C (n = 69), and respiratory syncytial virus (RSV) (n = 165). Novel viruses such as human metapneumovirus, human coronavirus NL63, human bocavirus, and human polyomaviruses WU and KI were also detected. There were 70 deaths, and one or more viruses were detected in 35 (50%) of these cases. Positivity only for influenza A virus (OR = 4.3, 95% CI = 1.3-14.6) was significantly associated with fatal outcome. From the blood culture, Burkholderia cepacia group (n = 9), Streptococcus pneumoniae (n = 4), Staphylococcus aureus (n = 4), Haemophilus influenzae (n = 1), and Salmonella C1 (n = 1) were also isolated.

CONCLUSION

Viruses were commonly detected in children with severe pneumonia in the Philippines. Hence, viral etiologies should be considered while developing better effective strategies to reduce child pneumonia-related deaths in developing countries.

Streptococcus pneumoniae capsular serotype 19F is more resistant to C3 deposition and less sensitive to opsonophagocytosis than serotype 6B

The polysaccharide capsule is a major virulence mechanism of Streptococcus pneumoniae, shielding the bacterium from phagocytes. Capsule types may differ in their abilities to resist immune defense. Antibody-mediated complement activation and opsonophagocytosis are crucial in protection against pneumococcus. Conjugate vaccine trials suggest imperfect protection against 19F. We have previously shown that significantly more anti-19F than anti-6B antibody is needed for killing in the opsonophagocytic assay (OPA). In this study, we explored whether the amount of C3 deposited on serotype 6B and 19F pneumococcal strains reflects their sensitivity to opsonophagocytosis. We compared clinical 6B and 19F nasopharyngeal, middle ear, and blood isolates as well as reference OPA strains (n = 16) for their sensitivity to opsonophagocytosis and C3 deposition. Sixfold anticapsular antibody concentrations were required for 50% opsonophagocytic killing of 19F compared to that of 6B strains. Serotype 19F was more resistant to C3 deposition than 6B. Complement deposition and opsonophagocytosis were dependent on the concentration of anticapsular antibodies. Differences between pneumococcal serotypes in antibody-mediated protection may partly be explained by the abilities of the capsules to resist complement deposition. These findings support previous studies suggesting that higher antibody concentrations to the capsular polysaccharide are needed for protection against disease caused by serotype 19F than that caused by 6B.