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

Streptococcus pneumoniae causes serious infections. Treatment is difficult because of the emergence of penicillin resistance in S. pneumoniae. Pneumococcal vaccines offer the promise of control and prevention of pneumococcal infections. Serotype prevalence and penicillin susceptibility data for a country will predict the usefulness of the vaccines in that country. In Kuwait, the 23-valent polysaccharide and the 7-valent conjugate vaccines are being used without knowledge of the prevalent serotypes in the country. To obtain the necessary background information, data on penicillin susceptibility and serogroups were obtained from 397 consecutive clinical isolates collected during 2004 and 2005. Two hundred fifty-three isolates (64%) were penicillin resistant, and resistance was significantly higher in patients ≤15 years old and among the upper respiratory tract and eye isolates. The most common serotypes were 23F, 19F, 6A, 6B, 14, and 19A. Among the penicillin-resistant strains, the most common serotypes were 23F, 19F, 6B, 14, and 9A. Among the invasive strains, the most common serotypes were 14, 23F, 19A, and 9V. The polysaccharide vaccine gave 82% coverage against invasive infections in all age groups >2 years. The coverage of the 7-valent conjugate vaccine against invasive serotypes in children ≤2 years old was 55%. This moderate coverage by the conjugate vaccine against invasive infections in children necessitates a revised strategy on the use of the present conjugate vaccine and shows the need for formulation of an improved vaccine for superior coverage for Kuwait and possibly other countries of the Arabian Gulf.     

Epidemiology of invasive pneumococcal infection in Taiwan: antibiotic resistance,serogroup distribution,and ribotypes analyses

From July, 1998, to June, 1999, pneumococcal isolates from 288 patients with invasive disease in Taiwan were serogrouped and tested for their susceptibility to various antibiotics. Automated ribotyping was used to study their molecular epidemiology. The mortality rate among those > or = 65 years was higher than those 18 or 19-64 years (p < 0.001). The total incidence of infection was significantly higher during the cooler season than the warmer season (p = 0.017). Among strains isolated from children aged < or = 18 years, 76% were not susceptible to penicillin, a rate that was significantly higher (p < 0.001) than that for adults (45%), as was the susceptibility to azithromycin, erythromycin, and trimethoprim-sulfamethoxazole (p < 0.005). The most prevalent serogroup encountered in the invasive isolates was 23, followed by 6, 14, 19, and 3. Isolation of Streptococcus pneumoniae in cerebrospinal fluid was at high rate in children under 5 years (p = 0.00012). Molecular typing revealed a high degree of polymorphism among the isolates. Among serogroup 23 and 19 isolates, a high proportion had the same ribotypes, the Taiwan23F-15 and Taiwan19F-14 isolates, suggesting the circulation of a Taiwanese epidemic strain. In Taiwan, S. pneumoniae isolates should be tested for their resistance profile for children < or = 18 years old, as these are more likely to harbor high-level resistance. Control of pneumococcal infection with the 7-valent-conjugated vaccine should also be considered because it is estimated that it would cover nearly 90% of the serotypes among pediatric invasive disease.     

Changes in Streptococcus pneumoniae serotypes causing invasive disease with non-universal vaccination coverage of the seven-valent conjugate vaccine

The pneumococcal seven-valent conjugate vaccine (PCV7) has been administered in Portugal since late 2001 through the private sector. To evaluate the impact of PCV7 use, the serotypes and antimicrobial susceptibility of pneumococci causing invasive disease in Portugal during 2003–2005 were determined and compared with available data for the period 1999–2002. Changes in serotype distribution compatible with the introduction of PCV7 were shown for children ≤5 years of age from 2003 onwards and for adults from 2004 onwards. PCV7 use with coverage of 43% of children with four doses in the 2004 birth cohort, although substantially below universal coverage, seems to have contributed to greatly reducing the proportion of invasive infections due to vaccine serotypes  4, 6B, 14 and 23F. Similarly, significant indirect effects on the serotype distribution of pneumococci causing infections in adults were noted, with reductions in the proportion of invasive infections caused by serotypes  4, 5 and 14. These changes were accompanied by an increase in the proportion of two non-vaccine serotypes: 19A isolates in all age groups and 7F isolates in adults. Whereas serotypes  6B, 14 and 19A were associated with multidrug resistance, isolates expressing serotypes  4 and 7F were fully susceptible for the most part. There were no changes in the proportion of resistant isolates within each serotype and, in spite of the changes in serotype prevalence, there was not an overall reduction in the proportion of infections caused by resistant pneumococci.     

Increasing Incidence of Penicillin- and Cefotaxime-resistant Streptococcus pneumoniae Causing Meningitis in India: Time for Revision of Treatment Guidelines?

Purpose: Pneumococcal meningitis is a life-threatening infection, requiring prompt diagnosis and effective treatment. Penicillin resistance in pneumococcal infections is a concern. Here, we present the antibiotic susceptibility profile of pneumococcal meningeal isolates from January 2008 to August 2016 to elucidate treatment guidelines for pneumococcal meningitis. Materials and Methods: Invasive pneumococcal isolates from all age groups, were included in this study. Minimum inhibitory concentrations for the isolates were identified by agar dilution technique and VITEK System 2. Serotyping of isolates was done by co-agglutination technique. Results: Out of 830 invasive pneumococcal isolates, 167 (20.1%) isolates were from meningeal infections. Cumulative penicillin resistance in pneumococcal meningitis was 43.7% and cefotaxime non-susceptibility was 14.9%. Penicillin resistance amongst meningeal isolates in those younger than 5 years, 5–16 years of age and those aged 16 years and older was 59.7%, 50% and 27.3%, respectively, with non-susceptibility to cefotaxime in the same age groups being 18%, 22.2% and 10.4%. Penicillin resistance amongst pneumococcal meningeal isolates increased from 9.5% in 2008 to 42.8% in 2016, whereas cefotaxime non-susceptibility increased from 4.7% in 2008 to 28.5% in 2016. Serotypes 14, 19F, 6B, 6A, 23F, 9V and 5 were the most common serotypes causing meningitis, with the first five accounting for over 75% of resistant isolates. Conclusions: The present study reports increasing penicillin resistance and cefotaxime non-susceptibility to pneumococcal meningitis in our setting. This highlights the need for empiric therapy with third-generation cephalosporins and vancomycin for all patients with meningitis while awaiting results of culture and susceptibility testing.     

Regional differences in serotype distribution,pneumococcal vaccine coverage,and antimicrobial resistance of invasive pneumococcal disease among German federal states

Continuous nationwide surveillance of invasive pneumococcal disease has been conducted in Germany for more than 15 years. In this study, 3724 isolates were included. A total of 2065 isolates were obtained from children under 16 years of age from 1997 to 2006, and 1659 isolates were obtained from adults aged 16 years and older between 2002 and 2006. Results were classified to federal states, and supra-regional trends were illustrated by classifying the federal states into the regions ‘North-West’, ‘North-East’ and ‘South’. Among childhood isolates, the most common serotypes were 14 (26.4%), 6B (7.7%), 23F (7.4%), 19F (7.1%), 1 (7.0%), 18C (6.2%), and 7F (5.6%). Serotype coverage for the 7-valent conjugate vaccine was 62.3%. For the 10-valent and 13-valent vaccines (both in development) the coverage was 75.5% and 84.8%, respectively. The 23-valent polysaccharide vaccine had a coverage of 87.3%. The coverage varies considerably among the federal states. Penicillin G resistance was observed in 7.4% of meningitis cases. In the non-meningitis group, no intermediate resistant or resistant strains were detected. Among adults, the most common serotypes were 14 (16.9%), 3 (9.2%), 4 (7.8%), 7F (7.5%), 1 (6.8%), and 9V (6.1%). Serotype coverage for the 7-valent conjugate vaccine was 46.5%. For the pneumococcal conjugate vaccines in development, the coverage was 61.1% (10-valent) and 76.3% (13-valent). The 23-valent polysaccharide vaccine had a coverage of 88.7%. Penicillin G resistance was observed in 6.4% of meningitis cases. Among these, considerably higher rates of resistance were observed in the North-East region (13.0%) than in the North-West (7.1%) and South (1.8%) regions.     

Distribution of serotypes and antibiotic resistance of invasive pneumococcal disease isolates among children aged 5 years and under in Saudi Arabia (2000–2004)

To determine vaccine coverage of invasive pneumococcal disease (IPD) in Saudi Arabian children aged 5 years and under, 350 IPD isolates were tested for antibiotic susceptibility. Of these 46%, 42% and 12% were penicillin-sensitive, pencillin-intermediate, and penicillin-resistant, respectively. Rates of resistance to erythromycin and cefotaxime were 26% and 6%, respectively. The potential serotype coverage of the PCV7 vaccine in Saudi Arabia among children <5 years of age is 62%, and vaccine coverage significantly improved in children <2 years of age, to reach 83% against IPD isolates. PCV7 is expected to have a substantial impact on the burden of invasive and antibiotic-resistant pneumococcal disease in Saudi Arabia.     

Serotypes of carriage and invasive isolates of Streptococcus pneumoniae in Brazilian children in the era of pneumococcal vaccines

Nasopharyngeal carriage of Streptococcus pneumoniae is a key factor in the development of invasive disease and the spread of resistant strains within the community. A single nasopharyngeal swab was obtained from 648 unvaccinated children aged <5 years, either healthy or with acute respiratory tract infection or meningitis, during the winters of 2000 and 2001. The overall pneumococcal carriage rate was 35.8% (95% CI 32.1-39.6). The pneumococcal serotypes found most frequently in the nasopharynx were 14, 6B, 6A, 19F, 10A, 23F and 18C, which included five of the seven serotypes in the currently licensed seven-valent conjugate vaccine (PCV7); serotypes 4 and 9V were less common. Serotypes 1 and 5 were isolated rarely from the nasopharynx. A comparison of 222 nasopharyngeal isolates with 125 invasive isolates, matched for age and time to the carrier isolates, showed a similar prevalence of penicillin non-susceptible pneumococci (PNSp) (19.8% and 19.2%, respectively). PNSp serotypes were similar (6B, 14, 19F, 19 A, 23B and 23F) for carriage and invasive disease isolates. The coverage of PCV7 for carriage isolates (52.2%) and invasive isolates (62.4%) did not differ significantly (p 0.06); similarly, there was no significant difference in PCV7 coverage for carriage isolates (34.5%) and invasive isolates (28.2%) of PNSp. These data suggest that PCV7 has the potential to reduce pneumococcal carriage and the number of carriers of PNSp belonging to vaccine serotypes.     

Serotype-specific penicillin resistance of Streptococcus pneumoniae in Germany from 1992 to 2008

A total of 12,137 isolates from invasive pneumococcal disease was collected between January 1, 1992, and December 31, 2008, by the German National Reference Center for Streptococci (NRCS). Data on penicillin susceptibility were available for 11,814 isolates, whereat 8837 isolates (74.8%) were from adults, and 2977 isolates (25.2%) originated from children. Overall, the leading serotypes were serotypes 14 (16.5% of serotyped isolates), 3 (8.1%), 7F (7.7%), 1 (7.4%), and 23F (6.0%). The overall nonsusceptibility rate of all isolates adds up to 5.5% (intermediate, 4.3%; resistant, 1.2%) when the CLSI 2006 guidelines were applied, and to 1.4% (intermediate, 0.2%; resistant, 1.2%) when using the CLSI 2009 guidelines. Generally, slightly higher resistance rates were observed among children than among adults. Serotypes contributing considerably to pneumococcal penicillin nonsusceptibility by a combination of frequency among invasive isolates and relatively high penicillin nonsusceptibility are 19A, 9V, 6B, 19F, 23F, and 14. While the nonsusceptibility among serotype 19A isolates increased considerably over the years, the development of nonsusceptibility rates among the other serotypes is less and more ambiguous.     

Distribution of Streptococcus pneumoniae serotypes responsible for penicillin resistance and the potential role of new conjugate vaccines in New Caledonia

Invasive pneumococcal disease is a significant cause of morbidity and mortality worldwide. The aim of this study was to establish the serotypes responsible for pneumococcal disease and the serotypes responsible for penicillin resistance in Noumea, New Caledonia. Isolates of Streptococcus pneumoniae from all body sites referred to the Microbiology Department of the Pasteur Institute in New Caledonia between May 1999 and May 2001 had serotyping and susceptibility testing performed. Basic demographic data on patients were also collected. A total of 298 isolates were included in the study. The most common serotypes were types 1 (20%), 23F (10%), 12F (8%), 19F (8%), and 6B (5%). The serotype distribution differed significantly with age, site of collection, and ethnicity. Overall, 280 of 298 (94%) of the isolates had serogroups that are included in the 23-valent vaccine. However, only 14 of 20 (70%) of the isolates associated with invasive disease from children younger than 5 years of age and 26 of 113 (23%) of invasive isolates from patients more than 5 years of age were included in the new 7-valent conjugate vaccine. Overall, reduced susceptibility to penicillin was found in 43 of 298 (14.4%) of the isolates, with 13% falling into the intermediate resistance category and only 5 (2%) being high-level resistant. A higher prevalence of penicillin resistance occurred in younger age groups and in European patients and involved specifically certain serotypes. The 7-valent conjugate pneumococcal vaccine has potential benefit for the New Caledonian population under 5 years of age and should be considered for future vaccines schedules.     

Antimicrobial resistance and serotypes of nasopharyngeal strains of Streptococcus pneumoniae in Brazilian adolescents

The aim of this study was to describe the frequency of antimicrobial-resistance and serotypes of nasopharyngeal pneumococcal isolates from adolescents. Clinical data and nasopharyngeal specimens for culture were collected from 1,013 adolescents as a part of a population-based study. A total of 83 isolates of Streptococcus pneumoniae were identified (8.2%). Seventy-four of the 83 isolates were serotyped. The median age of the 83 adolescents colonized by pneumococci was 14 years (mean 14 +/- 2.2 yrs); 55.4% were males. Intermediate resistance to penicillin was detected in 7.2% (6/83). No strain showed high resistance to penicillin. All isolates were susceptible to clindamycin, chloramphenicol, rifampin, and vancomycin; 37.3%, 18.1%, and 4.8% were resistant to trimethoprim-sulfamethoxazole, tetracycline, and erythromycin, respectively. The most frequent serotypes (5-10% of strains each) were 6B, 6A, 23F, and 18C among 28 serotypes/serogroups identified; 18.9% of the strains were nontypeable (NT). Intermediate resistance to penicillin was detected in serotypes 6B, 14, and NT. The rate of resistance to penicillin of nasopharyngeal isolates is low considering data from other studies about invasive strains recovered from children in Brazil. Serotype patterns are similar, except for type 14, which was unusually infrequent.     

Multicentre Study of the Molecular Epidemiology, Serotypes and Antimicrobial Susceptibility Patterns of Invasive Streptococcus pneumoniae Invasive Isolated from Children in the Ille de France Area

Between January 1997 and April 2002, 73 consecutive invasive strains of Streptococcus pneumoniae were isolated from children under 16 years of age in four hospitals in suburban Paris. Their genetic diversity was investigated by serotyping and analysis of pulsed-field gel electrophoresis restriction patterns. Antibiotic susceptibility patterns were analysed by disk susceptibility testing and determination of minimal inhibitory concentrations. The genetic basis of macrolide resistance was investigated by polymerase chain reaction. Studies of penicillin and vancomycin tolerance were performed for each strain. Despite the high prevalence (45.2%) of penicillin-nonsusceptible Streptococcus pneumoniae, resistance to amoxicillin (1.4%) was rare, and no strain was resistant to cefotaxime. Overall, 4.1% of pneumococcal strains were resistant to penicillin. Penicillin or vancomycin tolerance was not detected in any of the 73 strains studied. Of the erythromycin-resistant strains (48%), all but one carried the ermB gene. No strains showing a decreased susceptibility to ciprofloxacin (MIC, >4 mg/l) or overexpressing an efflux pump inhibited by reserpine were isolated. The serotypes found, in order of frequency, were as follows: 18C, 14, 6B, 19F, 19A, 9V, 23F, 1, 7F, 9A, 38. Strains of penicillin-nonsusceptible Streptococcus pneumoniae belonged predominantly to serotypes 14, 6B, 9V, 9A, 23F, 19F and 19A. The seven-valent conjugated vaccine covered 85.5% of the serogroups isolated in children under 2 years of age and 65.6% of the serogroups identified in children over 2 years of age. The genetic analysis showed a high identity for some serotypes, such as 14/9V, 6B and 23F. The use of the seven-valent conjugated vaccine is a critical measure to prevent invasive pneumococci infections in children in the Ille de France area.     

Reduction in pediatric invasive pneumococcal disease in the Basque Country and Navarre, Spain, after introduction of the heptavalent pneumococcal conjugate vaccine

This study evaluated the incidence of invasive pneumococcal disease, identified the causal serotypes, and tracked the evolution of the antibiotic susceptibility of Streptococcus pneumoniae isolates in the regions of the Basque Country and Navarre, Spain, before and after the introduction of the heptavalent pneumococcal conjugate vaccine. The study included all children aged between birth and 5 years diagnosed with bacteremia, meningitis, or bacteremic pneumonia caused by pneumococci. By the second year after introduction of the heptavalent pneumococcal conjugate vaccine, compared with the period 1998–2001, the incidence of invasive disease decreased by 64.3% in children less than 12 months of age, by 39.7% in children less than 24 months of age, and by 37.5% in children less than 60 months of age. The prevalence of clinical isolates of S. pneumoniae that lacked susceptibility to penicillin decreased by 58.2% among children less than 60 months of age. With an estimated coverage by four-dose heptavalent pneumococcal conjugate vaccine of 28–45% in 2003, the number of invasive pneumococcal infections in the Basque Country and in Navarre fell significantly after just 2 years of immunization, underscoring the importance of improving vaccination coverage under a universal childhood immunization program.     

Serotypes and antimicrobial susceptibilities of 1033 pneumococci isolated from children in Greece during 2001–2004

Pneumococci (n = 1033) isolated in the major paediatric hospitals of Athens during 2001-2004 from children with invasive infections (n = 186), non-invasive infections (n = 641) and healthy carriers (n = 206) were studied. The most prevalent serotypes were serotypes 14 (44.6%), 19F (43.5%) and 6B (22.8%) in invasive, non-invasive and carriage isolates, respectively. Among invasive isolates, the potential coverage by the seven-valent conjugate vaccine was 75.3%. Resistance rates to penicillin, amoxycillin, cefotaxime, erythromycin, co-trimoxazole, clindamycin, tetracycline and chloramphenicol were 44.6%, 2.7%, 1.2%, 43.6%, 43.5%, 12.4%, 34.7% and 5.9%, respectively. The M-phenotype accounted for 68.0% of the erythromycin-resistant isolates. All isolates were susceptible to ofloxacin.     

Capsular types and antibiotic sensitivity of pneumococci isolated from patients with serious infections in Belgium 1980 to 1988

A total of 2,765 strains ofStreptococcus pneumoniae isolated in more than 60 Belgian laboratories from blood or normally sterile body fluids between 1 November 1980 and 31 December 1988 were serotyped. From January 1983 onwards susceptibility of the strains to antimicrobial agents was also tested. The 2,765 isolates belonged to 57 of the 84 currently identified serotypes. Overall, 94 % of the strains were represented in the current 23-valent vaccine. The remaining 6 % of strains were distributed among 18 serotypes. More than 84 % of the middle ear fluid isolates came from children under ten years. Meningitis was commonest in children under five years and in adults over sixty years. Two-thirds of pneumococcal bacteremia isolates came from patients over 50 years. Of 1,933 isolates tested for susceptibility to antibiotics, 335 (17 %) were resistant to one or more of the agents tested (tetracycline, erythromycin, chloramphenicol, penicillin). Only 19 strains were relatively resistant to penicillin, while six were fully resistant. Resistance to erythromycin increased significantly from 5.2 % in 1986 to 11.5 % in 1988. The resistance ofStreptococcus pneumoniae to other antimicrobial agents did not change significantly during the study period. There was no relationship between age group and resistance to any of the agents tested.     

Serotype distribution and antimicrobial susceptibilities of nasopharyngeal isolates of Streptococcus pneumoniae from children hospitalized for acute respiratory illnesses in Hong Kong

Five hundred nineteen Streptococcus pneumoniae isolates from nasopharyngeal aspirates of 3,157 children (age, <16 years) participating in a respiratory surveillance study in Hong Kong in 2005 and 2006 indicated that 64.9% and 37.2% of the isolates were not susceptible to penicillin and cefotaxime, respectively. The rate of potential coverage by the seven-valent conjugate vaccine was 72.3%, and the rate increased to 74.6% for serogroup-specific types.     

Association of Serotypes of Streptococcus pneumoniae with Age in Invasive Pneumococcal Disease

A total of 7,764 isolates from patients with invasive pneumococcal disease (IPD) were collected from 1992 to June 2006. Data on serotypes were available for 5,022 isolates (64.7% of all invasive isolates). Some 54.0% of the isolates originated from adults ≥16 years of age, and 46.0% were from children <16 years of age. The leading serotypes were 14, 23F, 1, 6B, 7F, 3, and 4. The serotypes significantly more common in children were 14, 6B, 19F, and 18C, while among adults, serotypes 3 and 4 were predominant. Serotype 7F was statistically more prevalent among children <4 months old than among the other age groups. Among children aged ≥4 months and <1 year, serotype 19F occurred statistically more frequently; and among children aged ≥1 year to <5 years, serotypes 14, 6B, and 18C were overrepresented. The serotypes predominantly affecting patients younger than the remaining collective of patients were 14, 6B, 19F, and 18C, while patients with IPD caused by serotypes 3, 4, and 9V were older than the collective, on average.Streptococcus pneumoniae is among the most important pathogens in bacterial pneumonia, sepsis, and meningitis worldwide (1). The capsular polysaccharide of S. pneumoniae is known to be an important factor in the pathogenicity of the organism (7), and associations of the capsular serotypes with the severity of invasive pneumococcal diseases (IPDs) have been described (2, 14). IPDs are known to be much more frequent among young children and elderly persons than among older children and middle-aged adults (25). The results of several studies of the frequencies of pneumococcal serotypes and pneumococcal vaccine coverage have been published, but only few data on the serotype distribution among children and adults or different age groups are available. Studies from the United States (10, 19, 25), Canada (18), England and Wales (21), and Denmark (9), as well as the available meta-analyses (4, 15), refer to a diversity of age intervals. Although some studies contain statistics on the serotypes covered by the seven-valent pneumococcal conjugate vaccine (PCV7) and those not covered by the vaccine, no information on the association of individual serotypes with age are given. Another meta-analysis reported on the relative risk (odds ratio) of IPD caused by the various serotypes among all age groups subdivided into 10-year bands (26). Furthermore, in a 19-year nationwide surveillance study from Denmark, statistical analyses of the serotype distribution with age have been performed, but that study included only children aged 0 to 6 years (16). Some statistical data about individual serotypes and their association with age can also be found in the report of a study from the United States on the increased prevalence of pediatric pneumococcal serotypes in elderly adults. However, the study contained data only for adults aged ≥35 years (5).The aim of the study described here was to evaluate the association of serotypes of S. pneumoniae with age in IPD among isolates from all age groups sent to the German National Reference Center for Streptococci (NRCS) between 1992 and 2006.     

Serotyping and antibiotic resistance of Streptococcus pneumoniae isolated from pediatric infections in central Greece

Objective: To determine the distribution of serogroups/serotypes and antibiotic resistance pattern of Streptococcus pneumoniae isolated from pediatric infections in central Greece.
Methods: In total, 306 S. pneumoniae strains isolated from children, aged from 18 days to 14 years (median 18 months), during a 21-month period, from different specimen sources, were studied. Susceptibility testing was carried out by the Kirby-Bauer method and by the Etest, and serotyping by the Quellung reaction.
Results: Of the S. pneumoniae isolates, 3.9% were highly resistant to penicillin (PR), while 17.6% were intermediately resistant (IPR). PR and IPR isolates were found to be, in general, more resistant to other antibiotics than penicillin-susceptible isolates. The PR and IPR isolates belonged to the serogroup/serotypes 19, 23, 9, 6 and 14 (in descending order of frequency). The penicillin-susceptible isolates belonged to 20 different groups/serotypes, the most common being 19, 6, 14, 9, 3, 23 and 1 (in descending order of frequency). Serogroup 23 was often found to be multiresistant.
Conclusions: Resistance to penicillin in S. pneumoniae isolates is relatively low and differs according to the specimen type. All the pneumococcal serogroups/serotypes isolated from the children were found to be included in the 23-valent polysaccharide vaccine. Most of the children with a pneumococcal infection, however, were less than 2 years old and could not be protected by the existing vaccine.     

Serotyping and Antimicrobial Susceptibility of Group B Streptococcus Over an Eight-Year Period in Southern Taiwan

 The increase in penicillin resistance among pneumococci and viridans streptococci and the development of serotype-specific conjugate vaccine have increased the need for knowledge of the antimicrobial susceptibility and the capsular serotypes of group B streptococci. Over an 8-year period, 351 group B streptococcal isolates from southern Taiwan were tested for antimicrobial susceptibility and serotype determination. Eighty-seven percent of the isolates were typeable. Types III (28.5%) and V (27.1%) were the most common serotypes. The occurrence of type V isolates increased with age, while that of type III isolates decreased with age, showing a predominance in children less than 1 year of age. Of 118 isolates from cases of invasive infection, types Ia, Ib, II, III, IV, and V accounted for 12.7, 11.9, 0.8, 33, 1.7, and 26.3%, respectively. Using the agar dilution method, all isolates were found to be susceptible to penicillin, cefotaxime, and vancomycin, 99.4% to ofloxacin, 78.1% to chloramphenicol, 63.2% to azithromycin, 62.6% to erythromycin, 57.3% to clindamycin, and 2.8% to tetracycline. Chloramphenicol resistance was associated with type III isolates (59 of 100, 59%) and erythromycin and azithromycin resistance with type Ib isolates (25 of 33 [76%], and 21 of 33 [64%], respectively). Thus, 72% of the isolates from invasive infections were serotype III, V, or Ia, and penicillin remains the drug of choice for treatment or prophylaxis of group B streptococcal infections in southern Taiwan, despite the high prevalence of penicillin resistance among Streptococcus pneumoniae and viridans streptococci.     

Inferring the potential success of pneumococcal vaccination in Italy: serotypes and antibiotic resistance of Streptococcus pneumoniae isolates from invasive diseases

To evaluate the potential impact of antipneumococcal vaccination in Italy, Streptococcus pneumoniae isolates from invasive disease were collected from 65 laboratories in the years 1997-2000. Of the 503 isolates examined, 15% were from children <5 years and 34% from adults > or = 65 years. The most frequent serogroups were, in ranking order, 14, 19, 6, and 23. Overall, 93.8% of the isolates belonged to serogroups enclosed in the 23-valent polysaccharide vaccine. Among children isolates, serotypes 14, 6B, and 23F comprised 60% of the isolates; overall, 72% of the isolates belonged to serotypes included in the heptavalent conjugate vaccine. Penicillin nonsusceptible isolates (10%) belonged to a limited number of serogroups, being more common in serogroups 19 and 9 and in the nonvaccine serogroups 24 and 35. Erythromycin-resistant isolates (29%) belonged to several serogroups, more frequently to serogroups 14, 6, and 19. Both vaccines are potentially able to prevent the majority of resistant infections in the respective age groups in Italy.     

Antimicrobial susceptibility of Streptococcus pneumoniae from children attending day-care centers in a central Italian city

Objective: To undertake a survey of nasopharyngeal carriage of Streptococcus pneumoniae , which reflects strains causing infection, in 100 children under 3 years of age attending day-care centers in Frosinone, a city near Rome.
Methods: Fifty-three unique isolates of S. pneumoniae , isolated from 41 of the children tested, were tested for antimicrobial susceptibility to penicillin, cefotaxime, erythromycin, clindamycin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole.
Results: Resistance rates were as follows: penicillin, 20.7% (15% intermediate; 5.7% resistant); trimethoprim-sulfamethoxazole, 64.2%; erythromycin, 64.2%; clindamycin, 30.2%; tetracycline, 32.1%; and chloramphenicol, 3.8%. Except for three intermediate strains, all strains were susceptible to cefotaxime. Only five strains were susceptible to all of the antibiotics tested. An unusual finding of this study was that 23 of the 34 erythromycin-resistant strains were penicillin susceptible, whereas erythromycin-resistant strains found in other countries are predominantly penicillin resistant as well. In addition, 18 of the 34 erythromycin-resistant strains were susceptible to clindamycin. Serogroups 6, 14, 19 and 23 accounted for 84.9% of the isolates.
Conclusions: These data show that carriage of antibiotic-resistant pneumococci in children under 3 years of age is high in Frosinone, Italy. Information on resistance rates in pneumococcal disease in different age groups and on prevalence of drug resistance in other parts of the country is urgently needed.