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A Wasas

Publications and source records attributed to A Wasas.

16 recordsLinked to original sources
PubMed2001

Prevalence of serotypes and molecular epidemiology of Streptococcus pneumoniae strains isolated from children in Beijing, China: identification of two novel multiply-resistant clones.

Three-hundred and seventy-six strains of Streptococcus pneumoniae isolated from clinical specimens and nasopharyngeal swabs from children at daycare centers and hospitals in Beijing China, between January 1997 and March 1998, were serotyped. Twenty-seven different serotypes were identified. The most prevalent serotypes in the carriage isolates were 6A, 19F, 23F, and 15 and were found in 66.8% of cases. Serotype data indicate that 51.8% of carrier strains would be included in the 11-valent conjugate vaccine formulation, while inclusion of vaccine-related serotypes, increased the potential vaccine coverage to 79.4%. Serotypes 7, 6B, 23F, 19F, 15, and 3 accounted for 62% of clinical strains, with 70% vaccine-related serotypes. DNA fingerprinting of 47 penicillin resistant and 71 penicillin-susceptible/macrolide-resistant strains by BOX polymerase chain reaction (PCR), pulsed-field gel electrophoresis (PFGE), and penicillin binding protein (PBP)-fingerprinting identified two novel clones: one a serotype 23F multiresistant clone resistant to penicillin, tetracycline, erythromycin, clindamycin, and variably resistant to chloramphenicol and trimethoprim-sulphamethoxazole; and the second a multiresistant penicillin-susceptible, macrolide-resistant serotype 6A clone, highly resistant also to tetracycline, clindamycin, and trimethoprim-sulphamethoxazole. The macrolide resistance determinant in 89% of erythromycin-resistant strains tested (penicillin-susceptible and penicillin-resistant) was the erm gene, both the erm and mef genes were simultaneously found in 6%, and mef alone in 3.4%. The data demonstrates that macrolide resistant strains in China include clonal strains and strains with dual mef and erm resistance determinants.

Anti-Bacterial Agents↗
PubMed2001

Serotype 19f multiresistant pneumococcal clone harboring two erythromycin resistance determinants (erm(B) and mef(A)) in South Africa.

One hundred eighteen erythromycin-resistant Streptococcus pneumoniae (ERSP) strains (MICs of > or = 0.5 microg/ml) from five laboratories serving the private sector in South Africa were analyzed for the genes encoding resistance to macrolides. Sixty-seven ERSP strains (56.8%) contained the erm(B) gene, and 15 isolates (12.7%) contained the mef(A) gene. Thirty-six isolates (30.5%) harbored both the erm(B) and mef(A) genes and were highly resistant to erythromycin and clindamycin. DNA fingerprinting by BOX-PCR and pulsed-field gel electrophoresis identified 83% of these strains as belonging to a single multiresistant serotype 19F clone.

Anti-Bacterial Agents↗
PubMed2000

Antimicrobial resistance of nasopharyngeal isolates of Streptococcus pneumoniae and Haemophilus influenzae from children in the Central African Republic.

BACKGROUND: To assist the Central African Republic (CAR) develop national guidelines for treating children with pneumonia, a survey was conducted to determine antimicrobial resistance rates of nasopharyngeal isolates of Streptococcus pneumoniae (SP) and Haemophilus influenzae (HI). Secondary purposes of the survey were to identify risk factors associated with carriage of a resistant isolate and to compare the survey methods of including only children with pneumonia vs. including all ill children. METHODS: A cross-sectional survey of 371 ill children was conducted at 2 outpatient clinics in Bangui, CAR. RESULTS: In all 272 SP isolates and 73 HI isolates were cultured. SP resistance rates to penicillin, trimethoprim-sulfamethoxazole (TMP-SMX), tetracycline and chloramphenicol were 8.8, 6.3, 42.3 and 9.2%, respectively. All penicillin-resistant SP isolates were intermediately resistant. HI resistance rates to ampicillin, TMP-SMX and chloramphenicol were 1.4, 12.3 and 0%, respectively. The most common SP serotypes/groups were 19, 14, 6 and 1; 49% of HI isolates were type b. History of antimicrobial use in the previous 7 days was the only factor associated with carriage of a resistant isolate. Resistance rates were similar among ill children regardless of whether they had pneumonia. CONCLUSIONS: Resistance rates were low for antimicrobials recommended by the World Health Organization for children with pneumonia. We recommended TMP-SMX as the first line treatment for pneumonia in CAR because of its low cost, ease of dosing and activity against malaria.

Carrier State↗
PubMed2000

Impact of human immunodeficiency virus type 1 on the disease spectrum of Streptococcus pneumoniae in South African children.

BACKGROUND: HIV-infected children are at increased risk of developing invasive Streptococcus pneumoniae disease. OBJECTIVE: To determine the impact of the HIV epidemic on the epidemiology of invasive pneumococcal disease in hospitalized African children. METHODS: Children <12 years of age with invasive pneumococcal disease were enrolled between March, 1997, and February, 1999. RESULTS: The seroprevalence of HIV was 64.9% (146 of 225). In children with pneumococcal isolates from serogroups 6, 9, 14, 19 or 23 (pediatric serogroups), pneumonia and pneumonia with concurrent meningitis was more common in HIV-infected children (P = 0.03 and P = 0.003, respectively), whereas septic shock occurred more often in HIV-uninfected children (P = 0.0003). The overall burden of severe invasive pneumococcal disease was 41.7 (95% confidence interval, 26.5 to 65.6) fold increased in HIV-infected compared with HIV-uninfected children. Reduced susceptibility to penicillin (45.91% vs. 27.9%, P = 0.009), trimethoprim-sulfamethoxazole (44.5% vs. 19.0%, P = 0.0002) and multiple drug resistance was more common in HIV-infected than in HIV-uninfected children (24.0% vs. 6.4%, P = 0.01), respectively. The increased burden of disease and reduced antibiotic susceptibility of pneumococcal isolates in HIV-infected children was because of a heightened susceptibility to disease caused by pediatric serogroups in these children than in HIV-uninfected children (P = 0.01). Although the case fatality rates did not differ between HIV-infected and -uninfected children, mortality in HIV-infected children with advanced AIDS (Stage C, 22 of 61; 36.1%) was greater than that in children with moderate AIDS (Stage B, 12 of 85; 14.1%, P = 0.002). CONCLUSIONS: In children with invasive pneumococcal disease caused by the pediatric serogroups, HIV-infected children have more antibiotic-resistant isolates and have a different clinical presentation than do HIV-uninfected children.

Age Distribution↗
PubMed1998

Antibiotic resistance of nasopharyngeal isolates of Streptococcus pneumoniae from children in Lesotho.

Villages associated with the Lesotho Highlands Development Agency were randomized with a bias in favour of larger villages, and children < 5 years of age from cluster-randomized households in these villages were chosen for the assessment of antibiotic resistance in pneumococci. Children of the same age group attending clinics in the capital, Maseru, were selected for comparison. Nasopharyngeal cultures of Streptococcus pneumoniae from both groups of children were examined for antibiotic resistance and a questionnaire was used to assess risk factors for the acquisition of resistant strains. Carriage of penicillin- and tetracycline-resistant pneumococci was significantly higher among 196 Maseru children compared with 324 rural children (P < 0.05 and P = 0.01, respectively). Maseru children tended to visit clinics at an earlier age compared with their rural counterparts. The rural children were less exposed to antibiotics (P < 0.01), were less frequently hospitalized (P < 0.001), and rarely attended day care centres (P < 0.001). The very low incidence of antibiotic resistance in rural Lesotho and the higher incidence in Maseru are in stark contrast with the much higher frequencies found in the Republic of South Africa, many European countries, and the USA.

Anti-Bacterial Agents↗
PubMed1997

Streptococcus pneumoniae blood culture isolates from patients with and without human immunodeficiency virus infection: alterations in penicillin susceptibilities and in serogroups or serotypes.

We performed a 3-year retrospective study of Streptococcus pneumoniae blood culture isolates recovered at Baragwanath Hospital, Soweto, South Africa, from 1993 to 1995. The study group comprised 457 patients, including 98 children, of known human immunodeficiency virus (HIV) serostatus. Of these patients, 70 (30 [8.4%] of 359 adults and 40 [40.8%] of the 98 children) were infected with penicillin-resistant S. pneumoniae strains (minimal inhibitory concentration, > or = 0.12 microg/mL); 56 of these strains were intermediately resistant to penicillin. HIV-positive patients had significantly more penicillin-resistant isolates than did HIV-negative patients (43 [29.7%] of 145 HIV-positive patients vs. 27 [8.6%] of 312 HIV-negative patients; P < .001); this difference was found for both adults (19% vs. 4.3%; P < .001) and children (53.3% vs. 30.2%; P < .0343). Multiple resistance occurred more frequently in HIV-positive children (P = .02). HIV-positive adults had a statistically significant increase in the percentage of serogroups and serotype usually found in children and commonly associated with antimicrobial resistance, i.e., serotype 14 and serogroups 6, 19, and 23 (48% vs. 28.6%; P < .001). The increased prevalence of serogroups or serotypes usually found in children was also found among penicillin-susceptible strains. These data suggest that HIV-infected adults may again become susceptible to the serogroups or serotypes found in children.

AIDS-Related Opportunistic Infections↗
PubMed1997

Nasopharyngeal carriage of community-acquired, antibiotic-resistant Streptococcus pneumoniae in a Zambian paediatric population.

The emergence of antibiotic-resistant Streptococcus pneumoniae is an international health problem. Apart from South Africa few data on pneumococcal resistance are available for sub-Saharan Africa. This study examines the nasopharyngeal carriage and prevalence of antibiotic resistance in pneumococci isolated from 260 Zambian children aged < 6 years. Pneumococci were isolated from 71.9% of the children; the odds of carrying organisms were twice as high among children < 2 years of age compared with older children. Antibacterial resistance was found in 34.1% of the isolates; resistance to tetracycline, penicillin, sulfamethoxazole + trimethoprim, and chloramphenicol occurred in 23.0%, 14.3%, 12.7%, and 3.9% of the isolates, respectively. Only 4% of the isolates were resistant to three drugs. High-level resistance was found in all isolates resistant to tetracycline; but only intermediate level penicillin resistance was found. A total of 11.1% of the isolates demonstrated intermediate resistance to sulfamethoxazole + trimethoprim. Children aged < 6 months were less likely to carry antibiotic-resistant organisms. Antibiotic resistance in S. pneumoniae appears to be an emerging public health problem in Zambia, and the national policy for the empirical treatment of pneumococcal meningitis and acute respiratory tract infections may need to be re-evaluated. The establishment of ongoing surveillance to monitor trends in pneumococcal resistance should be considered.

Age Factors↗
PubMed1994

Cluster of an erythromycin-resistant variant of the Spanish multiply resistant 23F clone of Streptococcus pneumoniae in South Africa.

A multiply resistant serotype 23F pneumococcus was cultured from a 3-year-old child with otitis media and five carriers at the child's day-care centre in South Africa. Attempts to eradicate carriage with mupirocin failed. The strains were identical to the Spanish clone of multiply resistant pneumococci by serotype, antimicrobial susceptibility pattern, restriction analysis of the penicillin-binding protein 1A, 2B and 2X genes and by multilocus enzyme electrophoresis. The data suggest that this clone has acquired erythromycin resistance. A possible link between the index case and residence of a family member in Spain was found.

Adult↗
PubMed1994

Increasing prevalence of penicillin-resistant pneumococcal infections in children in southern Israel: implications for future immunization policies.

Although penicillin-resistant pneumococci (PR-PnC) are recognized as an increasing problem worldwide, data on the prevalence of these strains among pediatric patients are incomplete. The present study was conducted in southern Israel (1) to investigate the frequency of PR-PnC in invasive and middle ear infections in pediatric patients and (2) to assess the impact of resistance on the potential role of the candidate conjugate vaccines in preventing childhood PR-PnC infections. A total of 120 blood or cerebrospinal fluid isolates from 1987 to 1993 and 78 ear isolates from 1992 to 1993 were serogrouped and tested for susceptibility to antibacterial agents. The prevalence of PR-PnC among invasive isolates increased from 16% in the years 1987 to 1991 to 36% in 1992 to 1993 (P = 0.019). This increase was noted mainly for intermediately resistant strains (minimal inhibitory concentration, 0.12 to 1.0 micrograms/ml) whereas the prevalence of highly resistant strains was 3 and 2% for the 2 periods, respectively. The prevalence of PR-PnC among ear isolates in 1992 to 1993 was 42%. Resistance to other antimicrobial agents (one or more of the following: tetracycline, erythromycin, clindamycin and chloramphenicol) was found in 16 (8%) isolates, and multiple resistance (resistance to > or = 3 antibacterial agents) was found in 9 (5%) isolates. Sixty-five (99%) of the 66 resistant isolates belong to Serogroups 6, 14, 19 and 23. The prevalence of these 4 serogroups rose from 37% in 1987 to 1991 to 66% in 1992 to 1993 (P = 0.043). This rise was mainly because of Serogroup 23, the prevalence of which rose from 3% in 1987 to 1991 to 23% in 1992 to 1993 (P < 0.001). Eighty-five percent of all isolates belonging to Serogroup 23 were resistant to penicillin. Because Serogroups 6, 14, 19 and 23 are among the commonest pediatric pneumococcal strains, the newly developed conjugate pneumococcal vaccines contain these 4 serogroups. The selection of antibiotic-resistant strains has thus led to a change in the spectrum of serotypes causing invasive disease and to a situation of potential increase in vaccine coverage for the proposed pneumococcal conjugate vaccines.

Anti-Bacterial Agents↗
PubMed1992

[Pneumococcus-induced septicemia in normal and splenectomized rabbits].

A new rabbit model to study the consequences of splenectomy in host resistance to induced pneumococcal septicaemia is presented. A simple, fast, non-invasive and complication-free technique of bacterial inoculation into the rabbit airways, using transcutaneous cannulation of the trachea, is also described. Sixteen normal and 24 splenectomised animals were used. The optimal dose of pneumonococcus (serotype B, type III) was found to be 1 x 10(7) organisms. The above dose of bacteria given transtracheally failed to cause signs of pneumonia or death in any of the normal rabbits. However the same dose introduced using the same technique resulted reproducibly in the death of the low-resistance splenectomised animals.

Animals↗
PubMed1992

Antimicrobial resistance in Streptococcus pneumoniae: a South African perspective.

Resistance to penicillin among South African strains of Streptococcus pneumoniae increased from 4.9% in 1979 to 14.4% in 1990. Except for resistance to co-trimoxazole (44%), resistance to other antimicrobial agents remained relatively low. Multiply resistant strains belonged mainly to serovars 6B, 19A, 14, and, more recently, 23F. Use of chloramphenicol to treat meningitis caused by strains relatively resistant to penicillin proved to be unsatisfactory, probably because of the inadequate bactericidal activity of chloramphenicol against these strains. Spread of penicillin-resistant nasopharyngeal strains in pediatric wards was most common among children who received antimicrobial therapy. Penicillin-binding protein (PBP) patterns were shown to vary in resistant clinical strains. Interspecies transfer of penicillin resistance between Streptococcus mitis and S. pneumoniae was demonstrated and antigenic homology was found in PBPs 1A and 2B of strains belonging to these species. Restriction enzyme mapping following DNA amplification of the PBP 2B gene revealed six arrangements among South African strains within serogroup 19. Despite extensive studies in South Africa and several other countries, many questions with regard to the global problem of antimicrobial resistance among S. pneumoniae strains remain unanswered, especially those that relate to prevalence in developing regions of the world.

Carrier State↗
PubMed1988

Fatal infection caused by a multiply resistant type 3 pneumococcus.

The most virulent pneumococcal serotype (type 3) has not to date been associated with multiple antimicrobial resistance. We report an unusual gastrointestinal presentation of fatal septicemia caused by a multiply resistant type 3 pneumococcus in a setting of increasing prevalence of multiple resistance, including resistance to erythromycin, clindamycin, and tetracycline.

Adolescent↗
PubMed1986

Carriage of penicillin resistant pneumococci.

A survey of 303 urban and 156 rural children showed nasopharyngeal carriage of relatively resistant Streptococcus pneumoniae organisms in 14.2% and 19.2% of children, respectively. These organisms have minimum inhibitory concentrations for penicillin in the range of 0.12-1 microgram/ml. An analysis of 40 relatively resistant S. pneumoniae strains showed resistance to co-trimoxazole in 47.5%, trimethoprim in 42.5%, fusidic acid in 20%, tetracycline in 2.5%, and rifampicin in 5%. All the strains were susceptible to chloramphenicol and vancomycin, while the minimum inhibitory concentrations of third generation cephalosporins and imipenem were comparable with or lower than those of penicillin. Eighty three per cent of the strains tested belonged to serogroups 6 and 19. These findings are discussed in relation to the poor clinical response to treatment with penicillin for relatively resistant S. pneumoniae meningitis, and the minimum inhibitory concentrations of alternate agents under review for treatment of systemic pneumococcal disease are presented.

Anti-Bacterial Agents↗
PubMedDate not supplied

Nasopharyngeal carriage and antimicrobial resistance in isolates of Streptococcus pneumoniae and Haemophilus influenzae type b in children under 5 years of age in Botswana.

OBJECTIVES: A prospective survey was conducted to determine the prevalence of asymptomatic nasopharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae type b in children under 5 years of age in Botswana and to determine the antibiotic resistance patterns of these organisms to commonly used antimicrobial agents. METHODS: Children 2 months to 5 years of age (n = 249) were recruited from outpatient clinics in Gaborone and Francistown, and 29 were sampled from the pediatric wards at Princess Marina (Gaborone) and Nyangabgwe (Francistown) Hospitals. Nasopharyngeal specimens were collected and the carriage and antibiotic resistance of S. pneumoniae and H. influenzae type b were determined. Analyses of risk factors associated with carriage and resistance were performed. RESULTS: Streptococcus pneumoniae was isolated from 69% of the outpatient children in Gaborone and 85% of the children in Francistown; the carriage rate in hospitalized children was 36% and 33% in Gaborone and Francistown, respectively. Approximately half of the isolates at both sites were resistant to at least one antibiotic, the most common being cotrimoxazole and penicillin. Resistance to three or more antibiotics (multiple resistance) was found in less than 10% of the isolates. Most penicillin resistance at both sites was at the intermediate level; however, almost 20% of the isolates demonstrated high-level resistance to cotrimoxazole. The most prevalent serogroups or serotypes of antibiotic-resistant isolates were 14, 19F, 19A, 6A, 6B, and 4. No risk factors for antibiotic resistance were identified. Haemophilus influenzae type b was isolated from 8% of the children in Gaborone and from 3% of the children in Francistown. Almost a third of the isolates were resistant to ampicillin. CONCLUSIONS: The high levels of antibiotic resistance in pneumococci isolated from children in Botswana suggest that the clinical management of meningitis and otitis media with a b-lactam antibiotic may fail in a significant proportion of cases and that empiric first-line use of cefotaxime or ceftriaxone for meningitis and higher dose amoxicillin (90 mg/kg/day) for otitis media is recommended. The levels of penicillin resistance in this study would not impact on the management of pneumonia with amoxicillin.

Anti-Bacterial Agents↗