Implications of Streptococcus pneumoniae penicillin resistance and serotype distribution in Kuwait for disease treatment and prevention

The 13-valent pneumococcal conjugate vaccine (PCV13) does not appear to provide much protection on combined invasive disease due to the six PCV13 non-PCV7 serotypes 1, 3, 5, 6A, 7F, and 19A in Kuwait during 2010-2019

Kuwait started immunizing children <2 y age with the 7-valent pneumococcal conjugate vaccine, PCV7 from August 2007. PCV7 was replaced by the 13-valent conjugate vaccine, PCV13 from August 2010. In a previous analysis of the results for the period, August 2010-July 2013 (period II), there was no evidence of serotype-specific protection for invasive disease against the additional six serotypes to PCV7 present in PCV13 (non-PCV7 serotypes) as evidenced by isolation from blood and cerebrospinal fluid in any of the age groups, <2 y, 2-5 y, 6-50 y, 51-65 y, and >65 y and all ages, compared to the pre-vaccination period, August 2003-July 2006 (period I). In the current study, we allowed additional time, August 2013-July 2019 (period III) for better vaccine effect and repeated the analysis. We did not find any significant decrease of invasive disease due to the non-PCV7 serotypes of PCV13 in period III and combined II and III periods compared to period I. However, these comparisons showed significant reductions for four of the six and total serotypes of PCV7, and total serotypes of PCV13. Reduction for total PCV13 serotypes was contributed by serotypes of PCV7. It appears that the six non-PCV7 serotypes in PCV13 do not offer much protection. Some contributory factors for the poor effect of the non-PCV7 serotypes may be related to few cases with underpowered statistical analysis, lack of vaccine coverage data, method of vaccine efficacy analysis based on vaccine serotypes relative to all serotypes and unusual rise in non-typeable isolates post vaccination that would have masked true serotypes.

Effect of the introduction of pneumococcal conjugate vaccines on serotype prevalence in Kuwait and Saudi Arabia

BACKGROUND

Streptococcus pneumoniae infection is a major cause of morbidity and mortality. Although pneumococcal disease burden in Kuwait and Saudi Arabia is considered high, comprehensive surveillance data on pneumococcal conjugate vaccine (PCV) effects are lacking.

METHODS

Sterile isolates from patients in Kuwait (2003-2016) and Saudi Arabia (aged ≤5 years, 2000-2010; all patients, 2011-2015) were included. Serotyped isolates were classified by inclusion in the 7-valent (PCV7) or 13-valent PCV (PCV13); isolates of other serotypes were classified as "non-PCV13". Isolate frequency (number of isolates/year) and classification of isolates according to vaccine type were assessed by period (before PCV, after PCV7, and after PCV13 introduction).

RESULTS

In Kuwait, the frequency of collected isolates was highest after PCV7 introduction. Decreased frequency of PCV7 serotypes was seen after PCV13 introduction compared with before PCV and after PCV7 introduction. Increased frequency of the 6 additional serotypes in PCV13 and non-PCV13 serotypes was observed after PCV7 introduction with a subsequent decrease in the 6 additional serotypes in PCV13 and non-PCV13 serotypes after PCV13 introduction. The percentage of isolates of vaccine serotypes in Kuwait decreased over time. In Saudi Arabia, the frequency of collected isolates was highest after PCV7 introduction. An increased frequency of PCV7 serotypes was observed after PCV7 introduction, with a further decrease after PCV13 introduction. For the 6 additional serotypes in PCV13, an increased frequency was seen after PCV7 and PCV13 introduction compared to before PCV introduction. For non-PCV13 serotypes, an increased frequency was observed after PCV13 introduction compared to after PCV7 introduction. The percentage of isolates covered by PCV13 serotypes was similar across periods, while a substantial decrease in isolates covered by PCV7 was seen after PCV13 introduction.

CONCLUSION

PCVs in Kuwait and Saudi Arabia resulted in decreased frequency of some vaccine serotypes and an emergence of some non-PCV13 serotypes. Further investigation is warranted.

Serotype distribution and penicillin-non-susceptibility of Streptococcus pneumoniae causing invasive diseases in Kuwait: A 10-year study of impact of pneumococcal conjugate vaccines

OBJECTIVES

The impact of PCV7 and PCV13 on pneumococcal infections in Kuwait is not known. Therefore we evaluated the impact on pneumococcal serotype distribution and penicillin-non-susceptibility in invasive infections in Kuwait.

METHODS

Children < 2 y were given PCV7 from Aug 2006 to Jul 2010 (period I), and PCV13 from Aug 2010 to Jul 2013 (period II) with a pre-vaccination period from Aug 2003 to Jul 2006. Serotype and penicillin-non-susceptibility of blood and cerebrospinal fluid isolates from all ages were determined.

RESULTS

In <2 y old children, even with a small number of infections, a drop in PCV7 serotypes was evident after vaccination. For all age groups combined, in the pre-vaccination period, PCV7, PCV13, PCV13 non-PCV7 serotypes and penicillin-non-susceptibility constituted 53.2%, 72.6%, 19.4% and 6.5% of the isolates respectively. PCV7, PCV13 non-PCV7 serotypes and penicillin-non-susceptibility changed to 32.7%, 28.2% and 7.3% (period I) and 6.6%, 22.2% and 8.9% (period II).

CONCLUSIONS

Vaccines reduced invasive infections due to PCV7 serotypes.

Ketoacidosis at first presentation of type 1 diabetes mellitus among children: a study from Kuwait

We examined the frequency and severity of diabetic ketoacidosis (DKA) in 679 children and adolescents (0-14 years) at diagnosis of Type 1 Diabetes Mellitus (T1DM) in Kuwait. Between 1(st) January 2011 and 31(st) December 2013, all newly diagnosed children with diabetes were registered prospectively in a population-based electronic register. DKA was diagnosed using standard criteria based on the levels of venous pH and serum bicarbonate. At the time of diagnosis, mild/moderate DKA was present in 24.8% of the children, while severe DKA was present in 8.8%. Incidence of ketoacidosis was significantly higher in young children less than 2 (60.7% vs 32.4% p = <0.005) compared to children 2-14 years old, and a higher proportion presented with severe DKA (21.4% vs 8.3% p = <0.05). No association was seen with gender. Significant differences were found in the incidence of DKA between Kuwaiti and non-Kuwaiti children (31.1% vs 39.8%; p < 0.05). Family history of diabetes had a protective effect on the occurrence of DKA (OR = 0.44; 95% CI = 0.27-0.71). Incidence of DKA in children at presentation of T1DM remains high at 33.6%. Prevention campaigns are needed to increase public awareness among health care providers, parents and school teachers in Kuwait.

Epidemiology of community-acquired pneumonia and implications for vaccination of children living in developing and newly industrialized countries: A systematic literature review

This systematic review evaluated the epidemiology of community-acquired pneumonia in children <6 y of age within 90 developing and newly industrialized countries. Literature searches (1990–2011), based on MEDLINE, EMBASE, Cochrane, CAB Global Health, WHO, UNICEF, country-specific websites, conferences, health-technology-assessment agencies, and the reference lists of included studies, yielded 8,734 records; 62 of 340 studies were included in this review. The highest incidence rate among included studies was 0.51 episodes/child-year, for children <5 y of age in Bangladesh. The highest prevalence was in Chinese children <6 months of age (37.88%). The main bacterial pathogens were Streptococcus pneumoniae, Haemophilus influenzae and Mycoplasma pneumoniae and the main viral pathogens were respiratory syncytial virus, adenovirus and rhinovirus. Community-acquired pneumonia remains associated with high rates of morbidity and mortality. Improved and efficient surveillance and documentation of the epidemiology and burden of community-acquired pneumonia across various geographical regions is warranted.

Antimicrobial Susceptibilities and Distribution of Resistance Genes for β-Lactams in Streptococcus pneumoniae Isolated in Hamadan

BACKGROUND

β-lactams resistant Streptococcus pneumoniae are an emerging problem throughout the world. Several resistance mechanisms have been reported, including expression of drug-destroying enzymes such as β-lactamases, altered drug targets such as conformational changes in PBPs, decreased bacterial permeability, and increased drug efflux.

OBJECTIVES

The present study aimed to determine the relationship between the results of polymerase chain reaction identification of the Pbp1a, Pbp2b and Pbp2x genes (penicillin-binding proteins) and susceptibilities of β-lactam antibiotics against S. pneumoniae.

MATERIALS AND METHODS

Fifty five isolates of S. pneumoniae were obtained from clinical samples with antimicrobial tests. The susceptibilities of isolates to benzylpenicillin, imipenem, oxacillin, ceftazidime were determined. The resistance genotype was determined by the polymerase chain reaction with primers designed for the PBP genes.

RESULTS

The number of S. pneumoniae isolates resistant to benzylpenicillin, imipenem, oxacillin and ceftazidime were 94.5%, 100%, 100%, and 21.8%, respectively. Analysis of mutation in the genes for pbp showed that 85% of isolates had mutations in pbp2x, pbp2b and pbp1a. Susceptibility to benzylpenicillin was decreased once the number of mutated pbp genes in S. pneumonia increased. According to the results of this study, S. pneumoniae isolates showed reduced susceptibility due to accumulation of resistance genes.

CONCLUSIONS

We suggest that studies should be performed to evaluate changes in Minimum Inhibitory Concentration (MIC) values as well as genetic mutations in order to determine prevalence of S. pneumoniae resistance against antimicrobial agents.

Pneumococcal disease in the Arabian Gulf: recognizing the challenge and moving toward a solution

Pneumococcal disease has substantial incidence, morbidity and mortality in older adults. Decreased birth rates and longer lifespans indicate that the global population is aging, although rates of aging differ between countries [1]. In 2010, the proportion of the population aged >60 years in the general Arab Region was 7%, and this proportion is expected to rise to 19% by 2050 for the region as a whole [2]; the United Nations estimates for the individual countries of the Arabian Gulf by 2050 are 25.7%, 24.9%, 20.7%, 26.7% and 10.5% in the Kuwait, Bahrain, Qatar, United Arab Emirates (UAE) and Oman, respectively, which are comparable to the 26.9% predicted for the USA and lower than that predicted in European countries, in which the 2050 estimates are 32.7%, 34.0% and 38.1% for France, the UK and Germany, respectively [1]. Globally and in the Gulf Region, pneumococcal disease is an increasingly important public health burden in the elderly. The burden of pneumococcal disease can be reduced by effective vaccination programs, but the recommendations on pneumococcal vaccination in adults vary widely. The major barriers to vaccine implementation among healthcare professionals are an incomplete awareness of pneumococcal disease and the vaccination options in adults. The Gulf Advocate Group calls for healthcare providers in the countries of the Arabian Gulf (Kuwait, Bahrain, Qatar, United Arab Emirates and Oman) to support awareness and education programs about adult pneumococcal disease, particularly in high-risk groups such as those >65 years of age, those with type 2 diabetes mellitus, hematological malignancy, organ and bone marrow transplantation or chronic kidney or lung diseases and pilgrims undertaking the Hajj to improve pneumococcal disease surveillance and optimize and disseminate recommendations for adult vaccination. The Gulf Advocate Group recommends following the U.S. Centers for Disease Control and Prevention (CDC) guidelines for pneumococcal vaccination [3,4].

[Emergence of invasive pneumococcal disease caused by non-vaccine serotypes in the era of the 7-valent conjugate vaccine]

INTRODUCTION

There has been an increased incidence in invasive pneumococcal disease (IPD) produced by non-vaccine serotype (NVS) of Streptococcus pneumoniae after the introduction of PCV7. Our objective was to describe the epidemiological, clinical and microbiological characteristics of IPD caused by NVS in a tertiary hospital in Madrid.

PATIENTS AND METHODS

Retrospective (1998-2004) and prospective (2005-2009) study evaluating IPD caused by NVS in children. The study was divided into three periods: P1 (1998-2001) when PCV7 was not commercialized; P2 (2002-2005) with 40% vaccine coverage among children; and P3 (2006-2009) when the vaccine was added to the Childhood Immunization Schedule in Madrid.

RESULTS

We analyzed 155 cases of IPD. One hundred and fifty of these isolates were serotyped (100 were NVS). There was an increase in the prevalence of IPD from P1 (31%) to P2 (54%) and P3 (91%). The most relevant emerging serotypes were 19A, 7F, 1, 5, 3 and 15C. The most significant clinical syndromes produced by some specific serotypes were as follows: lower respiratory tract infection (LRTI) by serotypes 1, 3, 5 and 15C; LRTI, primary bacteremia and meningitis by serotype 19A; and primary bacteremia by serotype 7F (66%). The large majority (83.8%) of NVS were sensitive to penicillin.

CONCLUSIONS

There has been an increased prevalence of IPD caused by NVS since the introduction of PCV7. These changes should prompt the introduction of new pneumococcal vaccines, which include most of the NVS, in the childhood immunization calendar to prevent IPD in children.

Impact of pneumococcal conjugate vaccines on burden of invasive pneumococcal disease and serotype distribution of Streptococcus pneumoniae isolates: an overview from Kuwait

Diseases caused by Streptococcus pneumoniae are a major worldwide public health problem. The seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in Kuwait in August 2006 and the 13-valent vaccine, PCV13, in August 2010, for children aged <2 years, with catch-up programs for those from 2 to 5 years. The objective of this study was to evaluate the impact of vaccination on vaccine and non-vaccine serotype distribution in invasive and noninvasive S. pneumoniae isolates obtained in Kuwait from August 2006 through December 2011, as compared with previously published data. The susceptibility of all the isolates to penicillin was also evaluated. The study included all cases of noninvasive and invasive pneumococcal diseases (IPD) in children and adults among all age groups during this period. All isolates were serotyped using the Quellung reaction antisera and their susceptibility to penicillin was determined using the E test method. A total of 395 pneumococcal isolates were included in the study. After vaccine introduction, 23% of isolates were from children ≤5 years of age and 49% of cases in this age group were invasive, while 46% of isolates were from adults >50 years of age and 27% of cases in this age group were invasive. Two of 13 cerebrospinal fluid isolates and only one of 266 respiratory isolates obtained were penicillin resistant. For the post-vaccine period, the predominant serotypes in children ≤5 years were 19F, 19A, 6A, 8 and 15B for invasive isolates and 19F and 23F for noninvasive isolates and the predominant serotypes in adults >50 years of age were 14, 3, 1, 19F and 8 for invasive isolates and 19F, 23F, 6B, 14 and 19A for noninvasive isolates. Among children <2 years of age, coverage with PCV7, PCV10, and PCV13 was 34.6%, 38.5% and 61.5%, respectively, in the period post-vaccine introduction. Among children 2-5 years of age, corresponding coverage rates were 42.1%, 47.4% and 63.1%, respectively. A similar trend was noticed in adults, with coverage rates in the 51- to 65-years age group of 45.8%, 62.5% and 70.8% respectively. Compared with previously published findings, from the period prior to vaccine introduction, this represented an increased incidence in some non-PCV7 serotypes that are included in PCV13 (serotypes 1, 6A, and 3). In conclusion, with the emergence of new pneumococcal serotypes, broader vaccine coverage will aid in the prevention of IPD in children.

Infectious diseases in the Arabian Peninsula and Egypt

Infectious diseases are important causes of morbidity and mortality globally. Epidemiologically, differences in the patterns of infectious diseases and antimicrobial resistance exist across diverse geographical regions. In this review on infectious diseases in the Arabian Peninsula and Egypt, the epidemiology of tuberculosis, malaria and human immunodeficiency virus (HIV) infections will be addressed. The challenges of the hepatitis C epidemic in Egypt and the epidemiology of this infection across the region will be reviewed. In recent years, we have seen dengue endemicity become established, with major outbreaks in parts of the region. Emerging data also indicate that, across the region, there is an increasing burden of antibiotic resistance, with endemicity in healthcare settings and dissemination into the community. New challenges include the emergence of the Alkhurma haemorrhagic fever virus in Saudi Arabia. The annual Hajj pilgrimage in Saudi Arabia serves as a model for the control of infectious disease in mass gatherings. As most of these countries constantly experience a uniquely dynamic population influx in the form of expatriate workers, tourists, or pilgrims, concerted regional and international collaboration to address these public health concerns in a region that lies at the crossroads for the global spread of infectious pathogens is imperative.

Antimicrobial resistance among Gram-positive pathogens in Saudi Arabia

Several species of Gram-positive cocci are major nosocomial or community pathogens associated with morbidity and mortality. Here, we review the antimicrobial resistance among these pathogens in Saudi Arabia. In the last decades, antimicrobial resistance has increased among Staphylococcus aureus in the Kingdom with a growing prevalence of both nosocomial and community methicillin-resistant S. aureus (MRSA) isolates. As yet, no vancomycin-resistant MRSA have been reported, although isolates with reduced susceptibility to the drug have been noted. Currently, the prevalence of vancomycin-resistant entrococci (VRE) is low; however, VRE has been described in the Kingdom as well as Enterococcus faecalis and E. faecium isolates with high-level resistance to penicillin, sulfamethoxazole, macrolides, tetracycline, and aminoglycosides. In recent decades, the prevalence and rate of penicillin resistance and non-susceptibility among Streptococcus pneumoniae isolates have increased in Saudi Arabia. The organism remains, however, susceptible to other beta-lactams and to quinolones. On the other hand, resistance to co-trimoxazole and tetracyclines is high and resistance to macrolides is on the increase.

Reprint of: Serotyping and antibiotic susceptibility of Streptococcus pneumoniae strains isolated in Algeria from 2001 to 2010

INTRODUCTION

Pneumococcal infections are a major public health problem because of the virulence of this bacterium and its ability to develop resistance.

MATERIAL AND METHOD

Two hundred and ninety-four strains of Streptococcus pneumoniae were isolated from sterile (56.8%) and non-sterile samples (43.2%), from January 2001 to July 2010.

RESULTS

The interpretation of antibiotic susceptibility testing, according to CLSI criteria (M100-S21 2011), yielded a 25.2% overall resistance to penicillin, with 23.5% of strains isolated from CSF (meningitis), and only 1.7% in other samples. Resistance to cefotaxime was 8.1% (including 4.4% at a high level). The most common serotypes were: 14 (19.5%), 23F (9.7%), 6B (9.3%), 19F (5.4%), and serotype 1 (5%). The percentage of these serotypes isolated from normally sterile sites in children under 5 years of age was 31.25% for 14, 10.4% for 23F, 8.3% for 19F, 6.25% for 6B, and 4.2% for serotype 1. The theoretical vaccinal coverage against invasive infections in children under 2 years of age was 61.5%, 69.2%, and 76.9% for the 7-valent, 10-valent, and 13-valent conjugate vaccines, respectively. Penicillin non-susceptible Streptococcus pneumoniae (PNSP) strains accounted for 67.1, 68.6, and 72.8% for each of these three vaccines.

CONCLUSION

There was a variation of serotype rates compared to previous studies. The increase in pneumococcal antibiotic resistance is concerning, particularly for the treatment of pneumococcal infections in children and infants. Pneumococcal vaccination is not compulsory yet in Algeria.

Retrospective review of invasive pediatric pneumococcal diseases in a military hospital in the southern region of Saudi Arabia

BACKGROUND AND OBJECTIVES

Invasive pneumococcal disease (IPD) is associated with high case-fatality rates and serious chronic sequelae. The objective of this study was to assess the magnitude of invasive pneumococcal infections in a pediatric population without universal vaccination during childhood in a single hospital.

DESIGN AND SETTING

Retrospective review of all pediatric cases of invasive pneumococcal infection during a 7-year period.

PATIENTS AND METHODS

We reviewed the microbiological and clinical records of cases of IPD in children <13 years of age admitted to the Armed Forces Hospital, Southern Region, Saudi Arabia.

RESULTS

We identified 41 patients with IPD; 27 (66%) were <2 years of age. Four (50%) of those with pneumoccal meningitis were <2 years of age. The case fatality was 3 of 41 (7.3%) due to meningitis and 2 of 41 (5%) due to sepsis, with a case fatality of 5 (12%) due to meningitis and sepsis. Nine patients developed sequelae; of those with meningitis, 5 (73%) developed sequelae. Only 15 (41%) patients had predisposing medical conditions. The overall intermediate and high levels of pneumococcal resistance to penicillin and ceftriaxone were found to be 48.5%, 2.4% and 2.4%, 0%, respectively. None of the pneumococcal isolates were serotyped, and none of the patients had been vaccinated against pneumococcal infections in our hospital.

CONCLUSIONS

Despite the presence of a targeted immunization program, a considerable number of cases of invasive pneumococcal infections were reported among our pediatric population over a period of 7 years. Prospective studies in serotypes and antibiotic resistance from the southern region are needed to provide baseline information for the formulation and evaluation of a national prevention and control program.

Serotypes of Streptococcus pneumoniae isolates from children with invasive pneumococcal disease in Turkey: baseline evaluation of the introduction of the pneumococcal conjugate vaccine nationwide

Before use of the pneumococcal conjugate vaccine PCV7 became widespread in Turkey, 202 invasive pneumococcus isolates were analyzed. The most common serotypes were 19F and 6B. In children ≤2 years of age, the potential coverage rate of PCV7 was 69.5%. The most frequent non-PCV7 serotypes were 19A, 3, 1, 6A, and 8.

Serotype distribution and drug resistance in Streptococcus pneumoniae, Palestinian Territories

To determine antimicrobial drug resistance of Streptococcus pneumoniae serotypes, we analyzed isolates from blood cultures of sick children residing in the West Bank before initiation of pneumococcal vaccination. Of 120 serotypes isolated, 50.8%, 73.3%, and 80.8% of the bacteremia cases could have been prevented by pneumococcal conjugate vaccines. Serotype 14 was the most drug-resistant serotype isolated.

Serotype Prevalence and Penicillin-susceptibility of Streptococcus pneumoniae in Oman

OBJECTIVES

to determine the prevalent serotypes of Streptococcus pneumoniae and the rate of penicillin-nonsusceptibility among pneumococci in Oman.

METHODS

Pneumococcal isolates encountered during the period of September 2002 to December 2007 in the Royal Hospital were serotyped. Clinical information as well as the penicillin susceptibility reports were retrieved from the hospital information system and medical records.

RESULTS

120 strains of Streptococcus pneumoniae were isolated of which 85 strains were seroptyped. 20 different serotypes were identified, the most common seroptypes were 9A, 6B, 19F, 14 and 23F. 56% of the strains were not susceptible to pencillin, while 99% of these were susceptible to ceftriaxone. 74.3% and 46.1% of the serotypes are covered by the pneumococcal polysaccharide vaccine and the 7-valent pneumococcal conjugate vaccine respectively.

CONCLUSION

Certain few pneumococcal serotypes such as 9A, 6B and 19F are more prevalent in the Omani community than others. More than half of S. pneumoniae are not susceptible to penicillin while the great majority of the strains are susceptible to ceftriaxone.

Comparison of transformation frequencies among selected Streptococcus pneumoniae serotypes

Although there are over 90 serotypes of Streptococcus pneumoniae, antimicrobial resistance is predominantly found in a limited number of serotypes/serogroups, namely 6, 9, 14, 19 and 23. There is no compelling mechanism to account for this restriction. We aimed to determine whether serotypes commonly associated with drug resistance have higher transformation frequencies than those that are susceptible to antimicrobial agents. An in vitro investigation of the genetic transformation frequency of drug-resistant serotypes compared with that of susceptible serotypes under the influence of synthetic competence-stimulating peptides was performed. The transforming DNA was genomic DNA carrying a Tn916-like transposon containing the mefE gene that confers resistance to erythromycin. It was observed that serotypes 6, 9, 14, 19 and 23, which are highly associated with drug resistance, do not exhibit a higher degree of transformation efficiency than other serotypes. These findings suggest that the association of serotype with drug resistance is likely due to prolonged exposure to transforming DNA resulting from longer nasopharyngeal carriage and to a greater selective pressure from antimicrobials, particularly in children. This is the first study to compare the transformation frequencies of pneumococcal clinical isolates using genomic DNA that carries the composite Tn916-like element.