Serotype distribution and antibiotic susceptibility of Streptococcus pneumoniae strains in the south of Tunisia: A five-year study (2012–2016) of pediatric and adult populations

Systematic Literature Review of the Epidemiological Characteristics of Pneumococcal Disease Caused by the Additional Serotypes Covered by the 20-Valent Pneumococcal Conjugate Vaccine

Higher valency pneumococcal conjugate vaccines (PCV15 and PCV20) have been developed to address the disease burden of current non-vaccine serotypes. This review describes the epidemiological characteristics of serotypes beyond PCV13 (serotypes 8, 10A, 11A, 12F, 15B/C, 22F, and 33F; PCV20nonPCV13 serotypes). Peer-reviewed studies published between 1 January 2010 (the year PCV13 became available) and 18 August 2020 were systematically reviewed (PROSPERO number: CRD42021212875). Data describing serotype-specific outcomes on disease proportions, incidence, severity, and antimicrobial non-susceptibility were summarized for individual and aggregate PCV20nonPCV13 serotypes by age group and by type and duration of pediatric PCV immunization program. Of 1168 studies, 127 (11%) were included in the analysis. PCV20nonPCV13 serotypes accounted for 28% of invasive pneumococcal disease (IPD), although the most frequent serotypes differed between children (10A, 15B/C) and adults (8, 12F, 22F). In children, serotype 15B/C tended to be more frequently associated with pneumococcal meningitis and acute otitis media; in adults, serotype 8 was more frequently associated with pneumonia and serotype 12F with meningitis. Serotypes 10A and 15B/C in children and 11A and 15B/C in adults were often associated with severe IPD. Serotype 15B/C was also among the most frequently identified penicillin/macrolide non-susceptible PCV20nonPCV13 serotypes. These results could inform decision making about higher valency PCV choice and use.

Antibiotic resistance pattern, capsular types, and molecular characterization of invasive isolates of Streptococcus pneumoniae in the south of Tunisia from 2012 to 2018

BACKGROUND

Streptococcus pneumoniae remains a leading cause of morbidity and mortality worldwide. In this study, we sought to analyze serotype distributions, antibiotic resistance, and genetic relationships of 106 clinical invasive pneumococcal isolates recovered in Tunisia between 2012 and 2018, prior to the routine use of pneumococcal conjugate vaccines (PCV).

METHODS

We used multiplex PCR, the disk diffusion method and/or E-test, and multi-locus sequence typing (MLST).

RESULTS

The most frequent serotypes were 14 (17%), 19F (14.2%), and 3 (11.3%). Of the 106 S. pneumoniae isolates, 67.9% were penicillin non-susceptible (29.4% were resistant), 45.3% were amoxicillin non-susceptible (17% were resistant), and 16% were cefotaxime non-susceptible. For antibiotics other than β-lactams, resistance rates to erythromycin, tetracycline, cotrimoxazole, and chloramphenicol were 62.3, 33, 22.6, and 4.7%, respectively. Two isolates were non-susceptible to levofloxacin. Among 66 erythromycin-resistant pneumococci, 77.3% exhibited the cMLSB phenotype, and 87.9% carried ermB gene. All tetracycline-resistant strains harbored the tetM gene. The potential coverage by 7-, 10-, and 13-valent pneumococcal conjugate vaccines were 55.7, 57.5, and 81.1%, respectively. A multilocus sequence typing analysis revealed great diversity. Fifty different sequence types (STs) were identified. These STs were assigned to 10 clonal complexes and 32 singletons. The most common STs were 179, 2918, 386, and 3772 - related mainly to 19F, 14, 6B/C, and 19A serotypes, respectively.

CONCLUSIONS

This study demonstrated that the majority of the serotypes of invasive pneumococci in the Tunisian population were 14, 19F, and 3. Moreover, we noted a high degree of genetic diversity among invasive S. pneumoniae isolates. The highest proportions of antibiotic non-susceptible isolates were for penicillin, erythromycin, and tetracycline. Further molecular characteristics are required to monitor the genetic variations and to follow the emergence of resistant pneumococci for the post-vaccination era in Tunisia.

Serotype distribution and antimicrobial susceptibility of invasive Streptococcus pneumoniae isolates among adult and elderly population before and after introduction of pneumococcal conjugate vaccine in Casablanca, Morocco

BACKGROUND

Streptococcus pneumoniae (S. pneumoniae), remains a major cause of mortality and morbidity worldwide. The objective of this study was to determine the trends of invasive pneumococcal diseases (IPD) in adult and elderly population in Casablanca (Morocco) before and after introduction of pneumococcal conjugate vaccine (PCV) by determining the distribution of pneumococcal serotypes and antibiotic resistance profile of isolated strains.

METHOD

The proposed study is a retrospective laboratory-based surveillance of IPD in hospitalized adult (15-59 years old) and elderly (≥ 60 years old) patients in Ibn Rochd University Hospital Centre from 2007 to 2019 (13 years). All the 250 non-duplicate clinical invasive isolates from adult and elderly patients, confirmed as S. pneumoniae according to the laboratory standard identification procedures, are included in this study.

RESULTS

A significant decrease of the overall incidence in IPD was observed only in adults from 0.71 to 0.54/100000 populations (P  =  0.02) and to 0.47/100000 populations (P  =  0.0137) in the early and mature post-vaccine period respectively compared to the pre-vaccine period. Our results also showed a significant reduction in the overall prevalence of vaccine serotypes from 28.17 to 6.90% (P  =  0.0021) for the PCV-10 serotypes, and from 46.48 to 25.86% (P  =  0.0164) for the PCV-13 serotypes only in the mature post-vaccine period (2015-2019). In parallel, the rate of non-vaccine serotypes did not significantly change in the early post-vaccine period (2011-2014) while it increased considerably from 54 to 74.14% (P  =  0.0189) during the mature post-vaccine period. The rate of penicillin non-susceptible pneumococcal isolates decreased significantly from 23.94 to 8.77% (P  =  0.02) in adult patients, and the rate of cotrimoxazole non-susceptible pneumococcal isolates significantly decreased from 29.58 to 8.77% in the early post-vaccine period (P  =  0.003) and to 7.24% in the mature post-vaccine period (P  =  0.0007).

CONCLUSION

Although childhood vaccination has considerably reduced the incidence of IPD in adult population through the herd effect, IPD remain a real public health problem due to the alarming increase in non-vaccine serotypes (NVS) and the lack of herd effect among elderly population. The rate of antibiotic resistance was relatively low. Nevertheless, resistance constitutes a serious problem to the therapeutic arsenal due to the known capacity for genetic dissemination in the pneumococcus.

The impact of vaccination on the burden of invasive pneumococcal disease from a nationwide surveillance program in Lebanon: an unexpected increase in mortality driven by non-vaccine serotypes

BACKGROUND

The impact of pneumococcal conjugate vaccines (PCVs) on the burden of invasive pneumococcal disease (IPD) and serotype distribution was examined across age groups from data collected by the Lebanese Inter-Hospital Pneumococcal Surveillance Program.

METHODS

Between 2005 and 2020, 593 invasive Streptococcus pneumoniae isolates were collected from 79 hospitals throughout Lebanon. Serotypes and antimicrobial resistance (AMR) profiles were identified, and trends compared over 3 eras: PCV7, post-PCV7/ pre-PCV13, and PCV13 eras.

RESULTS

The prevalence of PCV7 serotypes decreased significantly from 43.6% in the PCV7 era to 17.8% during the PCV13 era (p<0.001). PCV13-only serotypes remained stable in the PCV13 compared to the post-PCV7 eras, especially serotypes 1 and 3, whereas non-vaccine types (NVT) increased throughout the study period, especially 24 and 16F. The mortality rate increased substantially from 12.5% (PCV7 era) to 24.8% (PCV13 era). A significant decrease in AMR was observed across the three study eras.

CONCLUSION

PCVs substantially impacted IPD and AMR in vaccinated and unvaccinated populations despite an increase in mortality driven by NVT. Broadening the recommendation of vaccination to include older age-groups, using higher valency vaccines, and implementing stringent antimicrobial stewardship are likely to further impact the burden of IPD.

A cost-effectiveness analysis of PHiD-CV compared to PCV13 in a national immunization program setting in Tunisia

Background

In response to the substantial clinical and economic burden of diseases caused by Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) in Tunisia, the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) was recently introduced into the national immunization program. However, there has yet to be a full-scale health economic analysis comparing currently available pneumococcal conjugate vaccines (PCVs) in Tunisia.

Methods

A Markov model that simulated the disease processes of invasive pneumococcal disease (IPD), pneumonia, and acute otitis media (AOM) over a newborn cohort lifetime was used to evaluate the cost-effectiveness/utility of PHiD-CV and the 13-valent pneumococcal conjugate vaccine (PCV13) from payer’s perspective, using 3% discounting. Vaccine effects were considered for up to 9 years of age.

Results

Vaccination with PHiD-CV or PCV13 was estimated to avert approximately 700 cases of IPD (200 meningitis, 500 bacteremia), and around 5,000 cases of all-cause pneumonia. However, PHiD-CV vaccination was estimated to avert around 4,000 additional AOM cases (18,000) versus PCV13 (14,000). Both PCVs were demonstrated to be cost-effective interventions, but PHiD-CV was estimated to generate additional cost savings of almost $1 million US dollars (USD) with similar levels of clinical benefits. An additional scenario which incorporated serotype-specific vaccine efficacy found no significant change in overall results.

Conclusion

PCVs are a cost-effective strategy to relieve the burden associated with diseases caused by S.pneumoniae and NTHi in Tunisia. PHiD-CV is more cost-effective than PCV13, generating similar health benefits, at a reduced net cost of almost $1 million USD per vaccinated cohort.

Pediatric Invasive Pneumococcal Disease (IPD) in Yogyakarta, Indonesia: A Case Series

Given the fact that invasive pneumococcal disease (IPD) has a high clinical burden, particularly among children in developing countries, data on its occurrence and clinical profile in Indonesia is still insufficient. We presented 3 cases of IPD in children who were admitted to Dr. Sardjito General Hospital, Yogyakarta, Indonesia between 2016 and 2019. While our first 2 patients had milder course of disease, our third patient who presented with meningoencephalitis had poor outcome. Risk factors shown in our cases were young age and malignancy history. Multiple antibiotic resistance was observed in our isolates. The fact that none of our patients have received pneumococcal vaccination marks the necessity of this vaccine especially for at-risk children.

Relationship Between Serotypes and Antimicrobial Nonsusceptibility of Streptococcus pneumoniae Clinical Isolates in Tunisia

Streptococcus pneumoniae remains a significant cause of morbidity and mortality worldwide despite the overall success of the vaccine programs. In Tunisia, pneumococcal conjugate vaccines (PCV)10 was introduced in the national immunization program in April 2019. We sought to determine the relationship between serotypes and antimicrobial nonsusceptibility of S. pneumoniae isolates recovered from clinical samples in the prevaccination period in the south of Tunisia. A total of 504 nonduplicate S. pneumoniae isolates collected between 2012 and 2018 were tested for antimicrobial susceptibility, among them 439 (87.1%) were serotyped. The most common serotypes were 19F (17.8%), 14 (15.3%), 3 (9.1%), 19A (8.2%), and 23F (7.3%). The proportions of isolates with serotypes covered by PCV7, PCV10, and PCV13 were 55.4%, 56.3%, and 77.9%, respectively. Three-quarters (74.4%) of pneumococcal isolates were nonsusceptible to penicillin, and about half (54.8%) were multidrug resistant. Penicillin nonsusceptibility was observed for all 19A and 23F isolates, and was significantly associated with serotypes 19F (odds ratio [OR]: 33.7) and 14 (OR: 8.7). A significant association with multidrug resistance was noted for serotypes 19A (OR: 10), 19F (OR: 9.4), 23F (OR: 8.6), and 6B (OR: 5.2). The alarming rates of pneumococcal antimicrobial nonsusceptibility and the strong association with the most prevalent serotypes compel microbiologists to monitor the impact of the PCV10 introduced recently in our national immunization program.

Nasopharyngeal carriage rate, serotype distribution, and antimicrobial susceptibility profile of Streptococcus pneumoniae isolated from children under five years old in Kotabaru, South Kalimantan, Indonesia

BACKGROUND

Streptococcus pneumoniae is a bacterial pathogen that colonizes the human nasopharynx. Colonization is frequently reported to be high in young children. In this study, we investigated the nasopharyngeal (NP) carriage rate, serotype distribution, and antibiotic susceptibility of S. pneumoniae in children under five years of age in Kotabaru, South Kalimantan, Indonesia.

METHODS

NP swab specimens were collected from 399 young children (mean age: 30 months) who participated in the Rampa Village Community Health Center, with 74% of the participants being Bajau children. S. pneumoniae was identified using optochin susceptibility and bile solubility tests. Serotyping was performed by sequential multiplex PCR, and antimicrobial susceptibility profiling was performed by disk diffusion and microdilution methods.

RESULTS

The NP carriage rate of S. pneumoniae was 45% (180/399). The most commonly serotypes were 6A/6B (18%), followed by 15B/15C (17%), 19F (16%), 34 (8%), and 23F (5%); 46% of them were identified as strains of the PCV13 vaccine type. Additionally, almost half of the pneumococcal isolates were non-susceptible to penicillin (40%), whereas non-susceptibility to tetracycline (36.8%), trimethoprim/sulfamethoxazole (29.7%), erythromycin (16.8%), chloramphenicol (9.7%), and clindamycin (8.6%) was also found. We identified 18% (n = 34) of S. pneumoniae isolates as multidrug-resistant (MDR) strains, and serotype 19F was the most common (74%) among them.

CONCLUSIONS

MDR S. pneumoniae vaccine type strains were dominated by serotype 19F. The implementation of a pneumococcal conjugate vaccine program in Indonesia might reduce MDR strains circulating in the community in the future.

Results from the Survey of Antibiotic Resistance (SOAR) 2015-18 in Tunisia, Kenya and Morocco: data based on CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints

OBJECTIVES

To determine antibiotic susceptibility of community-acquired respiratory tract infection (CA-RTI) isolates of Streptococcus pneumoniae and Haemophilus influenzae collected in 2015-18 from Tunisia, Kenya and Morocco.

METHODS

MICs were determined by CLSI broth microdilution and susceptibility was assessed using CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

S. pneumoniae isolates from Tunisia (n = 79), Kenya (n = 44) and Morocco (n = 19) and H. influenzae isolates (n = 74) from Tunisia only were collected and analysed. Low antibiotic susceptibility was observed in S. pneumoniae from Tunisia, with >90% susceptible only to the fluoroquinolones (all breakpoints), penicillin (CLSI IV and EUCAST high-dose) and ceftriaxone (CLSI, EUCAST high-dose and PK/PD breakpoints). In addition, isolate susceptibility in Kenya was >90% to amoxicillin and amoxicillin/clavulanic acid (CLSI and PK/PD breakpoints). Antibiotic activity was highest in Morocco, where ≥89.5% of pneumococci were susceptible to most antibiotics, excluding trimethoprim/sulfamethoxazole (68.4% by CLSI or PK/PD and 79%-84.2% by EUCAST), macrolides (79%-84.2% by all breakpoints) and cefaclor (0% by EUCAST and 52.6% by PK/PD). The majority (≥86.5%) of H. influenzae isolates from Tunisia were susceptible to most antibiotics by all available breakpoints, except ampicillin and amoxicillin (almost one-third were β-lactamase positive), trimethoprim/sulfamethoxazole (51.4%-56.8%), cefaclor (1.4% by PK/PD), cefuroxime (4.1% by EUCAST), macrolides (1.4%-2.7% by PK/PD) and cefdinir (66.2% by PK/PD). The application of different EUCAST breakpoints for low and higher doses for some of the antibiotics (amoxicillin, amoxicillin/clavulanic acid, ampicillin, penicillin, ceftriaxone, clarithromycin, erythromycin, levofloxacin and trimethoprim/sulfamethoxazole) allowed, for the first time in a SOAR study, the effect of raising the dosage on susceptibility to be quantified.

CONCLUSIONS

Low antibiotic susceptibility was observed in S. pneumoniae from Tunisia, but susceptibility was higher in isolates from Kenya and highest in those from Morocco. H. influenzae from Tunisia were highly susceptible to most antibiotics. These factors are important in decision making for empirical therapy of CA-RTIs.

The Burden of Invasive Vaccine-Preventable Diseases in Adults in the Middle East and North Africa (MENA) Region

Implementing vaccination programmes at the national level is key to managing vaccine-preventable diseases (VPDs) in the overall population. Although paediatric immunization programmes have significantly reduced the burden of VPD, disease burden in adults still poses a substantial challenge, particularly in low- and middle-income countries such as those within the Middle East and North Africa (MENA) region. Invasive bacterial diseases (IBDs) are an important public health concern within this region, although vaccines are available to prevent the three most common causative organisms associated with IBD: Neisseria meningitidis (NM), Streptococcus pneumoniae (SP), and Haemophilus influenzae (HI). For this review, three separate PubMed searches were used to identify English-language publications describing the epidemiology of NM, SP, and HI in adults within the MENA region. Of the 161 total publications retrieved among all 3 literature searches, 39 were included in this review (NM: 8 publications; SP: 27 publications; HI: 4 publications). Publications describing epidemiology in paediatric or overall populations were excluded. Overall, these studies generally observed a high burden of IBD among adults in this region. Although NM, SP, and HI are communicable diseases in several countries, the surveillance systems in the MENA region are largely inadequate, resulting in poor responses to outbreaks and hindering improvement in outcomes of communicable diseases. Improving IBD surveillance would provide necessary estimates of disease burden, resulting in better vaccination strategies and improved outcomes. In conclusion, the present review provides a summary of the available information on the epidemiology of vaccine-preventable IBD in adults within the MENA region and highlights the need for increased disease surveillance and preventive strategies in these countries.

Antimicrobial resistance among GLASS pathogens in conflict and non-conflict affected settings in the Middle East: a systematic review

BACKGROUND

In spite of the evident general negative effects of armed conflict on countries' health systems and populations' health outcomes, little is known about similar impacts of conflicts on the spread of antimicrobial resistances (AMR). This review was to address this evidence gap and describe: 1. Patterns of AMR in the Middle East (ME) and resistance profiles of pathogens included in the Global AMR Surveillance System (GLASS) supported by the World Health Organization; 2. Differences in proportions of AMR isolates between conflict and non-conflict countries.

METHODS

A systematic literature review was conducted following PRISMA guidelines and searching five electronic databases. Subject heading and free text were searched for "antimicrobial resistances" and "Middle East", to identify observational studies on AMR published from January 2011 to June 2018. Data were extracted from included articles on a predefined set of variables. Percentages of AMR were analysed as median and interquartile ranges. Risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

A total of 132 articles met the inclusion criteria. Included studies showed heterogeneity in study design, laboratory methods and standards for interpretation of results, and an overall high risk of bias. Main findings were the following: 1. High proportions of carbapenem resistance in Acinetobacter spp. (median 74.2%), and both carbapenem resistance (median 8.1 and 15.4% for E. coli and K. pneumoniae respectively) and ESBL-production (median 32.3 and 27.9% for E. coli and K. pneumoniae respectively) amongst Enterobacteriaceae. S. aureus isolates showed a median methicillin resistance percentage of 45.1%, while vancomycin resistance was almost absent. A median of 50% of the strains of S. pneumoniae showed non-susceptibility to penicillin. 2. Similar trends were observed in conflict and non-conflict affected countries.

CONCLUSIONS

There is a lack of standardization in the methodological approach to AMR research in the Middle East. The proportion of antibiotic resistances among specific GLASS pathogens is high, particularly among Acinetobacter spp.

Pilus islets and the clonal spread of piliated Streptococcus pneumoniae: A review

Pneumococci are a common cause of severe infections, such as otitis media, pneumonia, meningitis and bacteremia. Pili are detected in a small proportion of pneumococcal population, but these structures have recently been associated with bacterial virulence in humans. Therefore, the epidemiological relationships between pneumococcal pili, serotype and antimicrobial resistance are of interest. This study aims to discuss the virulence contribution of the Streptococcus pneumoniae pili and the epidemiological relationships among the pilus genes, antimicrobial resistance trends, regional serotypes and genotypic variations. Previous reports have characterized the pneumococcal pilus islet as a clonal feature in the pneumococcal serotypes that are covered by the pneumococcal conjugate vaccine (PCV), including serotypes 19A, 19F, 23F and 7F. Many of the pneumococcal molecular epidemiology network (PMEN) clones are piliated isolates that are also strongly associated with a high frequency of multidrug resistance. Most of these piliated pneumococcal isolates belong to a few clonal complexes (CC), such as CC320, CC199, CC271, CC191 and CC156. Additional molecular epidemiology and genomic studies, particularly whole genome sequence analysis (WGS), are needed to develop an in-depth understanding of the piliated pneumococcal isolates.

Phenotypic and molecular characterization of macrolide resistance mechanisms among Streptococcus pneumoniae isolated in Tunisia

Introduction. Streptococcus pneumoniae is responsible for many community infections, with the main ones being pneumonia and meningitis. Pneumococcus has developed increased resistance to multiple classes of antibiotics. The evolution of antibiotic resistance in pneumococcus was influenced by changes in serotype distribution under vaccine selection pressure.Aim. The aim of this study was to determine the genes involved in macrolide resistance, the antimicrobial susceptibility, the serotype distribution and the spread of international antibiotic-resistant clones among clinical isolates of S. pneumoniae.Methodology. We investigated 86 erythromycin-resistant S. pneumoniae strains isolated from respiratory (n=74) or non-respiratory (n=12) samples in Tunisia. Antimicrobial susceptibility was tested using the disk diffusion method. Macrolide-resistant strains were analysed by polymerase chain reaction (PCR) for ermA, ermB, mefA and msrD. We also investigated the macrolide resistance mechanisms in eight isolates (9.3%) by sequencing the L4 and L22 riboprotein-coding genes, plus relevant segments of the three 23S rRNA genes. Capsular serotypes were detected by multiplex PCR. Sequence types (STs) were explored using multilocus sequence typing (MLST).Results. Among the 86 studied strains, 70 (81.4 %) were resistant to penicillin G. The prevalent serotypes were 19F, 14, 19A and 23F. We observed that the cMLSB phenotype (66/86, 76.7%) was the most common in these pneumococci. In addition, ermB was the most frequent resistance gene. No mutation in ribosomal protein L22 or L4 or 23S rRNA was detected. Overall, 44 STs were identified in this study, including 16 that were described for the first time. Resistance to lincomycin, tetracycline and trimethoprim/sulfamethoxazole was observed in 55 (64 %), 34 (39.5 %) and 31 (36 %) isolates, respectively. Furthermore, an increase in fluoroquinolone use in particular may lead to the emergence of levofloxacin-resistant strains. Multidrug resistance was observed in 83 isolates (96.5%). Three global antibiotic-resistant clones were identified: Denmark¹⁴ ST230, Portugal^19F ST177 and Spain^9V ST156.Conclusion. This study shows that macrolide resistance among S. pneumoniae isolated in Tunisia is mainly related to target site modification. Our observations demonstrate a high degree of genetic diversity and capsular types among strains resistant to macrolides.

Whole-Genome Sequencing Analysis of Multidrug-Resistant Serotype 15A Streptococcus pneumoniae in Japan and the Emergence of a Highly Resistant Serotype 15A-ST9084 Clone

Since the introduction of pneumococcal conjugate vaccines (PCVs), an increase in the incidence of disease attributable to serotype 15A-ST63 (sequence type 63) pneumococci has been observed in many regions worldwide. We conducted a nationwide pediatric pneumococcal infection surveillance study between 2012 and 2014 in Japan. In the surveillance study, we detected multidrug-resistant serotype 15A-CC63 (clonal complex 63) strains (resistant to macrolides, penicillin, cefotaxime, and meropenem); in this study, we analyzed these resistant isolates to determine the dynamics and mechanism of resistance using whole-genome sequencing. In most of the penicillin-, cefotaxime-, and meropenem-resistant strains, recombination occurred in the pbp2x region, resulting in the acquisition of cefotaxime resistance in addition to penicillin and meropenem resistance. In the multidrug-resistant serotype 15A-CC63 strains, we identified a specific clone with ST9084, and all of the isolates were recovered from the Yamaguchi prefecture in Japan. All of the serotype 15A-ST9084 isolates had a novel pbp2x type (pbp2x-JP3) that was inserted by recombination events. The conserved amino acid motif profiles of pbp1a, pbp2b, and pbp2x of the strains were identical to those of serotype 19A-ST320. A Bayesian analysis-based date estimation suggested that this clone emerged in approximately 2002 before the introduction of the PCV in Japan. This clone should be monitored because serotype 15A is not contained in the currently used 13-valent PCV (PCV13), and it was resistant to beta-lactams, which are often used in a clinical setting.

Pneumococcal serotype distribution and antibiotic susceptibility in Malaysia: A four-year study (2014-2017) on invasive paediatric isolates

OBJECTIVE

This study was performed to analyze the serotype distribution of Streptococcus pneumoniae causing invasive pneumococcal disease (IPD) in children aged 5 years and under in Malaysia and to assess the antimicrobial resistance.

METHODS

From 2014 to 2017, a total of 245 invasive S. pneumoniae isolates from children ≤5 years of age were received from hospitals all around Malaysia. All isolates were identified and subjected to serotyping and antimicrobial susceptibility testing.

RESULTS

Of the 245 isolates, 117 (48.0%) were from children aged <1year, 46 (19.05%) were from children aged 1-2 years, and 82 (33.0%) were from children aged 2-5 years. The most common serotypes were 14 (26.9%), 6B (19.6%), 19A (11.8%), 6A (10.6%), and 19F (6.9%) and vaccine coverage was 88.2% for PCV13, 64.1% for PCV10, and 63.3% for PCV7. Resistance to penicillin was 0.2% for non-meningitis cases and 22.2% for meningitis cases; erythromycin resistance was reported in 42.9%, co-trimoxazole in 35.9%, and tetracycline in 42.9%.

CONCLUSIONS

Serotypes 14, 6B, 19A, 6A, and 19F were the most common serotypes isolated from children with IPD in Malaysia during this pre-vaccination era. The lack of reports on the serotype distribution has limited action for the implementation of PCV in the national immunization programme (NIP). The information from this study may benefit future policies for the introduction of PCV in the Malaysian NIP and ultimately may reduce the morbidity and mortality among children in Malaysia.

Cost-Effectiveness of the Pneumococcal Conjugate Vaccine (10- or 13-Valent) Versus No Vaccination for a National Immunization Program in Tunisia or Algeria

INTRODUCTION

To evaluate the expected impact of the Algeria national immunization program (NIP) and potential impact for a Tunisia NIP, this study assessed the public health and economic value of vaccination, through a cost-effectiveness analysis, for a PCV13 or PCV10 NIP, compared with no vaccination.

METHODS

A decision-analytic model was programmed in Microsoft Excel™ and adapted to evaluate the clinical and economic outcomes of PCV vaccination. Assuming a steady state, the model estimated invasive pneumococcal disease (IPD; bacteremia and meningitis), all-cause pneumonia (inpatient and outpatient), and all-cause otitis media cases as well as the associated costs from a payer perspective. The base case scenario assumed direct effects for both PCVs and indirect effects (against IPD) for PCV13 only.

RESULTS

In Algeria, compared with no vaccination program, PCV13 would save 2177 lives and avoid nearly 349,000 cases of IPD, pneumonia, and AOM at a highly cost-effective value of $308 per QALY. In Tunisia, PCV13 would save 308 lives and avoid 1305 cases of IPD, 4833 cases of pneumonia, and 54,957 cases of AOM at a highly cost-effective value of $848 per QALY. PCV10 prevented 1224 deaths and 270,483 cases of disease in Algeria and prevented 172 deaths and 56,610 cases in Tunisia. PCV10 was cost-effective in both Algeria at $731/QALY and in Tunisia at $1366/QALY.

CONCLUSION

The ongoing NIP in Algeria is projected to reduce the impact and economic toll of pneumococcal disease in Algeria. If an NIP were also introduced in Tunisia, a commensurate impact would be expected. PCV NIPs are highly cost-effective, highly impactful public health interventions.

FUNDING

Pfizer.

Epidemiology of common resistant bacterial pathogens in the countries of the Arab League

No uniformly organised collection of data regarding antimicrobial resistance has occurred in the countries of the Arab League. 19 countries of the Arab League have published data for antimicrobial susceptibility for the WHO priority organisms, and seven of 14 of these organisms are included in this Review (Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Acinetobacter baumannii, Salmonella spp, Staphylococcus aureus, and Streptococcus pneumoniae). Although E coli and Klebsiella spp resistance to third-generation cephalosporins is common in all countries, with prevalence reaching more than 50% in Egypt and Syria, carbapenem resistance is emerging, albeit with a prevalence of less than 10%. Conversely, a large amount of carbapenem resistance has been reported for P aeruginosa and A baumannii across the Arab League, reaching 50% and 88% of isolates in some countries. As for Salmonella spp, the prevalence of fluoroquinolone resistance has exceeded 30% in several areas. With regards to the Gram-positive pathogens, the prevalence of meticillin resistance in S aureus is reported to be between 20% and 30% in most countries, but exceeds 60% in Egypt and Iraq. The prevalence of penicillin non-susceptibility among pneumococci has reached more than 20% in Algeria, Egypt, Morocco, Saudi Arabia, and Tunisia. These findings highlight the need for structured national plans in the region to target infection prevention and antimicrobial stewardship.