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Fulltext The role of interspecies recombination in the evolution of antibiotic-resistant pneumococci

D'Aeth JC, van der Linden MP, McGee L, de Lencastre H, Turner P, Song JH, et al.

Elife, 2021 Jul 14;10.
PMID: 34259624 DOI: 10.7554/eLife.67113

Multidrug-resistant Streptococcus pneumoniae emerge through the modification of core genome loci by interspecies homologous recombinations, and acquisition of gene cassettes. Both occurred in the otherwise contrasting histories of the antibiotic-resistant S. pneumoniae lineages PMEN3 and PMEN9. A single PMEN3 clade spread globally, evading vaccine-induced immunity through frequent serotype switching, whereas locally circulating PMEN9 clades independently gained resistance. Both lineages repeatedly integrated Tn916-type and Tn1207.1-type elements, conferring tetracycline and macrolide resistance, respectively, through homologous recombination importing sequences originating in other species. A species-wide dataset found over 100 instances of such interspecific acquisitions of resistance cassettes and flanking homologous arms. Phylodynamic analysis of the most commonly sampled Tn1207.1-type insertion in PMEN9, originating from a commensal and disrupting a competence gene, suggested its expansion across Germany was driven by a high ratio of macrolide-to-β-lactam consumption. Hence, selection from antibiotic consumption was sufficient for these atypically large recombinations to overcome species boundaries across the pneumococcal chromosome.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Fulltext The upper respiratory tract microbiome of indigenous Orang Asli in north-eastern Peninsular Malaysia

Cleary DW, Morris DE, Anderson RA, Jones J, Alattraqchi AG, A Rahman NI, et al.

NPJ Biofilms Microbiomes, 2021 01 05;7(1):1.
PMID: 33402693 DOI: 10.1038/s41522-020-00173-5

Much microbiome research has focused on populations that are predominantly of European descent, and from narrow demographics that do not capture the socio-economic and lifestyle differences which impact human health. Here we examined the airway microbiomes of the Orang Asli, the indigenous peoples of Malaysia. A total of 130 participants were recruited from two sites in the north-eastern state of Terengganu in Peninsular Malaysia. Using 16S rRNA sequencing, the nasal microbiome was significantly more diverse in those aged 5-17 years compared to 50+ years (p = 0.023) and clustered by age (PERMANOVA analysis of the Bray-Curtis distance, p = 0.001). Hierarchical clustering of Bray-Curtis dissimilarity scores revealed six microbiome clusters. The largest cluster (n = 28; 35.4%) had a marked abundance of Corynebacterium. In the oral microbiomes Streptococcus, Neisseria and Haemophilus were dominant. Using conventional microbiology, high levels of Staphylococcus aureus carriage were observed, particularly in the 18-65 age group (n = 17/36; 47.2% 95% CI: 30.9-63.5). The highest carriage of pneumococci was in the <5 and 5 to 17 year olds, with 57.1% (4/7) and 49.2% (30/61), respectively. Sixteen pneumococcal serotypes were identified, the most common being the nonvaccine-type 23A (14.6%) and the vaccine-type 6B (9.8%). The prevalence of pneumococcal serotypes covered by pneumococcal conjugate vaccines support introduction into a Malaysian national immunisation schedule. In addition, the dominance of Corynebacterium in the airway microbiomes is intriguing given their role as a potentially protective commensal with respect to acute infection and respiratory health.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Fulltext Molecular detection and genotypic characterisation of Streptococcus pneumoniae isolated from children in Malaysia

Goh SL, Kee BP, Abdul Jabar K, Chua KH, Nathan AM, Bruyne J, et al.

Pathog Glob Health, 2020 02;114(1):46-54.
PMID: 32003298 DOI: 10.1080/20477724.2020.1719325

Streptococcus pneumoniae (S. pneumoniae) is one of the main causative agents of pneumococcal diseases. To date, more than 90 distinct serotypes have been identified. Implementation of vaccines has caused a drastic reduction in vaccine-serotype pneumococcal diseases but increase in cases due to non-vaccine serotype has been observed in Malaysia. However, further investigation on different serotype incidence in Malaysia is needed and the rate of pneumococcal vaccination for new-born babies in Malaysia remains low. The recent emergence of drug-resistant S. pneumoniae (DRSP) has also been a global concern, especially penicillin resistance. This study determined the serotypes of S. pneumoniae strains (n = 95) isolated from nasopharyngeal specimens from children admitted to UMMC from 2013 to 2015. In accordance with previous studies, PCR result showed 40% of NT isolates were successfully typed as 3 less common serotypes, namely 9N/L, 17A, and 23B. The repetitive-element PCR (REP-PCR) result revealed genetic variations among the strains whereby five major clusters were observed at the similarity of 80% by clustering analysis based on fingerprint data. Penicillin-binding proteins (pbps) of selected isolates were studied by PCR and sequencing. Three strains with ≤19-mm diameter zone for Oxacillin Disc Diffusion (ODD) test previously were recorded to have mutation on all pbp1a, pbp2b, and pbp2x with MIC of 4 µg/ml, which were penicillin-intermediate resistance according to the CLSI breakpoints.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Fulltext Multidrug-resistant Streptococcus pneumoniae causing invasive pneumococcal disease isolated from a paediatric patient

Arushothy R, Ramasamy H, Hashim R, Raj A S S, Amran F, Samsuddin N, et al.

Int J Infect Dis, 2020 Jan;90:219-222.
PMID: 31682962 DOI: 10.1016/j.ijid.2019.10.037

The emergence of non-vaccine multidrug-resistant Streptococcus pneumoniae serotypes is on rise. This study was performed to investigate a highly resistant serotype 15A S. pneumoniae isolated from the blood specimen of a 20-month-old patient who died of her infection. The SS40_16 isolate was resistant to erythromycin, co-trimoxazole, tetracycline, and chloramphenicol, as well as to penicillin, ceftriaxone, and cefotaxime (using meningitis cut-off points, Clinical and Laboratory Standards Institute). The isolate belonged to sequence type 1591 (ST1591) and was related to CC81 clonal complex, suggesting the possibility of horizontal gene transfer. Scanning electron microscopy comparison between resistant and sensitive pneumococcal isolates also indicated similar phenotypic characteristics that confer high resistance. The emergence of highly resistant non-vaccine pneumococci is of great concern to public health and in the clinical setting. Pneumococcal surveillance programs represent a crucial tool, not only for determining the impact of pneumococcal conjugate vaccines, but also for monitoring the selective pressure of serotype replacement with regard to the treatment of invasive pneumococcal disease.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Status of the effectiveness of contact lens disinfectants in Malaysia against keratitis-causing pathogens

Abjani F, Khan NA, Jung SY, Siddiqui R

Exp Parasitol, 2017 Dec;183:187-193.
PMID: 28919333 DOI: 10.1016/j.exppara.2017.09.007

The aim of this study was (i) to assess the antimicrobial effects of contact lens disinfecting solutions marketed in Malaysia against common bacterial eye pathogens and as well as eye parasite, Acanthamoeba castellanii, and (ii) to determine whether targeting cyst wall would improve the efficacy of contact lens disinfectants. Using ISO 14729 Stand-Alone Test for disinfecting solutions, bactericidal and amoebicidal assays of six different contact lens solutions including Oxysept®, AO SEPT PLUS, OPTI-FREE® pure moist®, Renu® fresh™, FreshKon® CLEAR and COMPLETE RevitaLens™ were performed using Manufacturers Minimum recommended disinfection time (MRDT). The efficacy of contact lens solutions was determined against keratitis-causing microbes, namely: Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Acanthamoeba castellanii. In addition, using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, we determined whether combination of both agents can enhance efficacy of marketed contact lens disinfectants against A. castellanii trophozoites and cysts, in vitro. The results revealed that all contact lens disinfectants tested showed potent bactericidal effects exhibiting 100% kill against all bacterial species tested. In contrast, none of the contact lens disinfectants had potent effects against Acanthamoeba cysts viability. When tested against trophozoites, two disinfectants, Oxysept Multipurpose and AO-sept Multipurpose showed partial amoebicidal effects. Using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, the findings revealed that combination of both agents in contact lens disinfectants abolished viability of A. castellanii cysts and trophozoites. Given the inefficacy of contact lens disinfectants tested in this study, these findings present a significant concern to public health. These findings revealed that targeting cyst wall by using cyst wall degrading molecules in contact lens disinfecting solutions will enhance their efficacy against this devastating eye infection.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
In vitro activity of Tedizolid phosphate against multidrug-resistant Streptococcus pneumoniae isolates from Asian countries

Baek JY, Kang CI, Kim SH, Ko KS, Chung DR, Peck KR, et al.

Diagn Microbiol Infect Dis, 2016 Jun;85(2):218-20.
PMID: 27083121 DOI: 10.1016/j.diagmicrobio.2016.02.022

Tedizolid phosphate is a second-generation oxazolidinone prodrug that is potential activity against a wide range of Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, penicillin-resistant streptococci, and vancomycin-resistant enterococci. The in vitro activity of tedizolid and other comparator agents against multidrug-resistant (MDR) pneumococci from various Asian countries were evaluated. Of the S. pneumoniae clinical pneumonia isolates collected during 2008 and 2009 from 8 Asian countries (Korea, Taiwan, Thailand, Hong Kong, Vietnam, Malaysia, Philippines, and Sri Lanka), 104 isolates of MDR pneumococci were included in this study. Antimicrobial susceptibility testing for 18 antimicrobial agents was performed by broth microdilution method. Tedizolid was highly active against pneumococci. All isolates tested were inhibited at a tedizolid minimum inhibitory concentration (MIC) value of ≤0.25μg/ml (ranged from ≤0.03μg/ml to 0.25μg/ml). The MIC50 and MIC90 of tedizolid against MDR pneumococci were both 0.12μg/ml, while MIC50 and MIC90 of linezolid were 0.5μg/ml and 1μg/ml, respectively. In addition, tedizolid maintained the activity against S. pneumoniae regardless of the extensively drug-resistant (XDR) phenotype of the isolates. The activity of tedizolid was excellent against all types of MDR pneumococci, exhibiting and maintaining at least 4-fold-greater potency compared to linezolid, regardless of resistance phenotypes to other commonly utilized agents. Tedizolid has the potential to be an agent to treat infections caused by MDR pneumococci in the Asia.

Matched MeSH terms: Streptococcus pneumoniae/drug effects*
Fulltext Antimicrobial Activity of Novel Synthetic Peptides Derived from Indolicidin and Ranalexin against Streptococcus pneumoniae

Jindal HM, Le CF, Mohd Yusof MY, Velayuthan RD, Lee VS, Zain SM, et al.

PLoS One, 2015;10(6):e0128532.
PMID: 26046345 DOI: 10.1371/journal.pone.0128532

Antimicrobial peptides (AMPs) represent promising alternatives to conventional antibiotics in order to defeat multidrug-resistant bacteria such as Streptococcus pneumoniae. In this study, thirteen antimicrobial peptides were designed based on two natural peptides indolicidin and ranalexin. Our results revealed that four hybrid peptides RN7-IN10, RN7-IN9, RN7-IN8, and RN7-IN6 possess potent antibacterial activity against 30 pneumococcal clinical isolates (MIC 7.81-15.62µg/ml). These four hybrid peptides also showed broad spectrum antibacterial activity (7.81µg/ml) against S. aureus, methicillin resistant S. aureus (MRSA), and E. coli. Furthermore, the time killing assay results showed that the hybrid peptides were able to eliminate S. pneumoniae within less than one hour which is faster than the standard drugs erythromycin and ceftriaxone. The cytotoxic effects of peptides were tested against human erythrocytes, WRL-68 normal liver cell line, and NL-20 normal lung cell line. The results revealed that none of the thirteen peptides have cytotoxic or hemolytic effects at their MIC values. The in silico molecular docking study was carried out to investigate the binding properties of peptides with three pneumococcal virulent targets by Autodock Vina. RN7IN6 showed a strong affinity to target proteins; autolysin, pneumolysin, and pneumococcal surface protein A (PspA) based on rigid docking studies. Our results suggest that the hybrid peptides could be suitable candidates for antibacterial drug development.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Genotypic characterization of Malaysian human isolates of Streptococcus pneumoniae from carriage and clinical sources

Shakrin NN, Masri SN, Taib NM, Nordin SA, Jamal F, Desa MN

Comp Immunol Microbiol Infect Dis, 2014 Dec;37(5-6):347-54.
PMID: 25467035 DOI: 10.1016/j.cimid.2014.10.005

This study characterized carriage and clinical pneumococcal isolates for serotypes, penicillin susceptibility, virulence genes and restriction fragment length polymorphism (RFLP) pattern of penicillin binding protein (PBP) genes. DNA fingerprint of isolates was generated by BOX-PCR. Majority of serotypes were 23F followed by 19F, 19A and 6A. Twenty-four percent of isolates were penicillin non-susceptible (PNSP). All of the targeted virulence genes were detected in all isolates with the exception of pili; 20.6% (n=22) for PI-1 and 14.0% (n=15) for PI-2. Of the 13 isolates which carried both PI-1 and PI-2, 10 were of clinical origin. Digested pbp-DNA produced three PBP-RFLP profiles for pbp1a (A1 to A3), six profiles for pbp2b (B1 to B6) and seven for pbp2x (X1 to X7) mostly in PNSPs. Based on BOX-PCR analysis, the majority of isolates were genetically diverse with a small number of potentially related isolates carrying pili genes. No obvious genotypic association was observed pertaining to carriage and clinical origin of isolates.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Genotypic characterization of Streptococcus pneumoniae serotype 19F in Malaysia

Jeevajothi Nathan J, Mohd Desa MN, Thong KL, Clarke SC, Masri SN, Md Yasin R, et al.

Infect Genet Evol, 2014 Jan;21:391-4.
PMID: 24342879 DOI: 10.1016/j.meegid.2013.11.026

Streptococcus pneumoniae is an epidemiologically important bacterial pathogen. Recently, we reported the antibiotic susceptibility patterns of a limited collection of pneumococcal isolates in Malaysia with a high prevalence of erythromycin resistant strains. In the present study, 55 of the pneumococcal isolates of serotype 19F were further analysed by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The generated genotypic patterns were then correlated with the antibiograms previously reported. Forty-seven different PFGE profiles (PTs) were obtained, showing that the isolates were genetically diverse. MLST identified 16 sequence types (STs) with ST-236 being predominant (58.2%), followed by ST-81 (10.3%). Among the ST-236 isolates, 22 were erythromycin resistant S. pneumoniae (ERSP) and 15 were trimethoprim/sulfamethoxazole (TMP/SMX) resistant, while among ST-81, four isolates were ERSP and two were TMP/SMX resistant. The high prevalence of erythromycin resistant serotype 19F isolates of ST-236 in this study has also been reported in other North and South East Asian countries.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Fulltext Regional epidemiology of invasive pneumococcal disease in Asian adults: epidemiology, disease burden, serotype distribution, and antimicrobial resistance patterns and prevention

Hung IF, Tantawichien T, Tsai YH, Patil S, Zotomayor R

Int J Infect Dis, 2013 Jun;17(6):e364-73.
PMID: 23416209 DOI: 10.1016/j.ijid.2013.01.004

To summarize published data on the clinical and economic burden, epidemiology, antimicrobial resistance levels, serotype prevalence, and prevention strategies for pneumococcal disease among adults in Asia.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Antimicrobial activity of the crude extract of Piper sarmentosum against methicilin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Vibrio cholera and Streptococcus pneumoniae

Fernandez L, Daruliza K, Sudhakaran S, Jegathambigai R

Eur Rev Med Pharmacol Sci, 2012 Jul;16 Suppl 3:105-11.
PMID: 22957424

The emergence of novel diseases caused by microbial pathogens and the undesirable side effects of certain antibiotics has been a recent dilemma in the medical arena. Consequently, it has stirred the discovery of many naturally occurring agents which could possibly provide important ramifications against various pharmacological targets and to combat various ailments. The main aim of the present study was to determine the antimicrobial activity of the crude methanolic extract of Piper (P.) sarmentosum against methicillin resistant Staphylococcus aureus (MRSA), Escherichia coli, Vibrio cholera and Streptococcus pneumoniae.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Fulltext Capsular serotype and antibiotic resistance of Streptococcus pneumoniae isolates in Malaysia

Le CF, Palanisamy NK, Mohd Yusof MY, Sekaran SD

PLoS One, 2011;6(5):e19547.
PMID: 21603602 DOI: 10.1371/journal.pone.0019547

BACKGROUND: Streptococcus pneumoniae is a major causative agent of severe infections, including sepsis, pneumonia, meningitis, and otitis media, that has since become a major public health concern. In this study, the serotypes distribution of pneumococcal isolates was investigated to predict the efficacy of the 7-valent pneumococcal conjugate vaccine (PCV7) among the Malaysian populations.
METHODOLOGY/PRINCIPAL FINDINGS: A total of 151 clinical isolates were serotyped using multiplex PCR assays. Out of them, there were 21.2% penicillin-resistant, 29.1% penicillin-intermediate, and 49.7% penicillin-susceptible S. pneumoniae strains. Serotypes detected among the Malaysian isolates were 1, 3, 10A, 11A/11D, 12F/12A, 14, 15A, 15B/15C, 16F, 18C/18B/18A/18F, 19A, 19F, 23F, 35B, 35F/47F, 6A/6B, 7C/7B/40, 7F/7A, 9V/9A, and 34. Serotype 19F and 23F were the two most prevalent serotypes detected. Serotypes are highly associated with invasiveness of isolates (p = 0.001) and penicillin susceptibility (p<0.001). Serotype 19F was observed to have increased resistance against penicillin while serotype 19A has high invasive tendency. Age of patients was an important factor underlying the pneumococcal serotypes (p = 0.03) and clinical sites of infections (p<0.001). High prevalence of pneumococcal isolates were detected among children <5 years old at nasopharyngeal sites while elderly adults ≥60 years old were at increased risk for pneumococcal bacteremia.
CONCLUSION/SIGNIFICANCE: Current study revealed that a number of serotypes, especially those associated with high penicillin resistance, have been formulated in the PCV7. Therefore, the protections expected from the routine use of PCV7 would be encouraging for the Malaysian. However, it is not possible to predict serotypes that might become predominant in the future and hence continued surveillance of circulating serotypes will be needed.

Matched MeSH terms: Streptococcus pneumoniae/drug effects*
Distribution of CBP genes in Streptococcus pneumoniae isolates in relation to vaccine types, penicillin susceptibility and clinical site

Desa MN, Sekaran SD, Vadivelu J, Parasakthi N

Epidemiol Infect, 2008 Jul;136(7):940-2.
PMID: 17678563

Choline-binding proteins (CBP) have been associated with the pathogenesis of Streptococcus pneumoniae. We screened, using PCR, for the presence of genes (cbpA, D, E, G) encoding these proteins in 34 isolates of pneumococci of known serotypes and penicillin susceptibility from invasive and non-invasive disease. All isolates harboured cbpD and cbpE whereas cbpA and cbpG were found in 47% and 59% respectively; the latter were more frequent in vaccine-associated types and together accounted for 77% of these isolates. No association was observed with penicillin susceptibility but 85% of non-invasive isolates were positive for these genes.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Detection of pbp2b and ermB genes in clinical isolates of Streptococcus pneumoniae

Kumari N, Navaratnam P, Sekaran SD

J Infect Dev Ctries, 2008 Jun 01;2(3):193-9.
PMID: 19738350

BACKGROUND: Streptococcus pneumoniae is a major human pathogen. The emergence of penicillin resistant strains since the 1970s has been life threatening and the evolution of the bacteria have enabled itself to develop resistance to many other antibiotics such as the macrolides and the fluoroquinolones. This study aims to characterize S. pneumoniae isolates for the presence of penicillin and macrolide resistance genes.
METHODOLOGY: One hundred and twenty clinical isolates of S. pneumoniae were obtained from patients of University Malaya Medical Centre (UMMC). The strains were screened using a multiplex real-time PCR method for the presence of alterations in the genes encoding the penicillin binding proteins: pbp2b, macrolide resistance determinant ermB and the pneumolysin gene, ply. Dual-labelled Taqman probes were used in the real-time detection method comprising three different genes labeled with individual fluorophores at different wavelengths. One hundred and twenty isolates from bacterial cultures and isolates directly from blood cultures samples were analyzed using this assay.
RESULTS: A multiplex PCR comprising the antibiotic resistance genes, ermB and and pneumolysin gene (ply), a S. pneumoniae species specific gene, was developed to characterize strains of S. pneumoniae. Out of the 120 pneumococcal isolates, 58 strains were categorized as Penicillin Sensitive Streptococcus pneumoniae (PSSP), 36 as Penicillin Intermediate Streptococcus pneumoniae (PISP) and 26 as Penicillin Resistant Streptococcus pneumoniae (PRSP). All the 58 PSSP strains harboured the pbp2b gene while the 36 PISP and 26 PRSP strains did not harbour this gene, thus suggesting reduced susceptibility to penicillin. Resistance to erythromycin was observed in 47 of the pneumococcal strains while 15 and 58 were intermediate and sensitive to this drug respectively. Susceptibility testing to other beta-lactams (CTX and CRO) also showed reduced susceptibility among the strains within the PISP and PRSP groups but most PSSP strains were sensitive to other antibiotics.
CONCLUSION: The characterization of pneumococcal isolates for penicillin and erythromycin resistance genes could be useful to predict the susceptibility of these isolates to other antibiotics, especially beta-lactams drugs. We have developed an assay with a shorter turnaround time to determine the species and resistance profile of Streptococcus pneumoniae with respect to penicillin and macrolides using the Real Time PCR format with fluorescent labeled Taqman probes, hence facilitating earlier and more definitive antimicrobial therapy which may lead to better patient management.

Matched MeSH terms: Streptococcus pneumoniae/drug effects
Molecular characterization of genes encoding the quinolone resistance determining regions of Malaysian Streptococcus pneumoniae strains

Kumari N, Subramaniam G, Navaratnam P, Sekaran SD

Indian J Med Microbiol, 2008 5 1;26(2):148-50.
PMID: 18445951

Genes encoding the quinolones resistance determining regions (QRDRs) in Streptococcus pneumoniae were detected by PCR and the sequence analysis was carried out to identify point mutations within these regions. The study was carried out to observe mutation patterns among S. pneumoniae strains in Malaysia. Antimicrobial susceptibility testing of 100 isolates was determined against various antibiotics, out of which 56 strains were categorised to have reduced susceptibility to ciprofloxacin (>or=2 microg/mL). These strains were subjected to PCR amplification for presence of the gyrA, parC , gyrB and parE genes. Eight representative strains with various susceptibilities to fluoroquinolones were sequenced. Two out of the eight isolates that were sequenced were shown to have a point mutation in the gyrA gene at position Ser81. The detection of mutation at codon Ser81 of the gyrA gene suggested the potential of developing fluoroquinolone resistance among S. pneumoniae isolates in Malaysia. However, further experimental work is required to confirm the involvement of this mutation in the development of fluoroquinolone resistance in Malaysia.

Matched MeSH terms: Streptococcus pneumoniae/drug effects*
Comparison of susceptibility test methods to detect penicillin susceptibility in Streptococcus pneumoniae isolates

Mohd Nasir MD, Parasakthi N

Malays J Pathol, 2004 Jun;26(1):29-33.
PMID: 16190104

The increasing prevalence of penicillin-resistant Streptococuus pneumoniae urges for fast and accurate susceptibility testing methods. This study evaluated the comparability of three commonly used techniques; disk diffusion, E-test and agar dilution, to detect penicillin susceptibility in clinical isolates of S. pneumoniae. Fifty pneumococcal isolates, obtained from patients at the University of Malaya Medical Centre, were selected to include both penicillin-susceptible strains and those that had decreased susceptibility (resistant and intermediate) to penicillin. The minimum inhibitory concentration (MIC) values of penicillin to serve as the reference was determined by the agar dilution method in which, based on the MIC breakpoints recommended by the National Committee for Clinical Laboratory Standards (NCCLS), 27 strains had decreased susceptibility to penicillin with 17 strains resistant and 10 intermediate. Comparing to the agar dilution method, oxacillin disk diffusion test detected all strains with decreased penicillin susceptibility as such while E-test showed a close agreement of susceptibility (92%) of the isolates to penicillin. This confirmed that oxacillin is a good screening test for S. pneumoniae isolates with decreased susceptibility to penicillin while E-test is very reliable for rapid and accurate detection of penicillin susceptibility.

Matched MeSH terms: Streptococcus pneumoniae/drug effects*
High prevalence of antimicrobial resistance among clinical Streptococcus pneumoniae isolates in Asia (an ANSORP study)

Song JH, Jung SI, Ko KS, Kim NY, Son JS, Chang HH, et al.

Antimicrob Agents Chemother, 2004 Jun;48(6):2101-7.
PMID: 15155207

A total of 685 clinical Streptococcus pneumoniae isolates from patients with pneumococcal diseases were collected from 14 centers in 11 Asian countries from January 2000 to June 2001. The in vitro susceptibilities of the isolates to 14 antimicrobial agents were determined by the broth microdilution test. Among the isolates tested, 483 (52.4%) were not susceptible to penicillin, 23% were intermediate, and 29.4% were penicillin resistant (MICs >/= 2 mg/liter). Isolates from Vietnam showed the highest prevalence of penicillin resistance (71.4%), followed by those from Korea (54.8%), Hong Kong (43.2%), and Taiwan (38.6%). The penicillin MICs at which 90% of isolates are inhibited (MIC(90)s) were 4 mg/liter among isolates from Vietnam, Hong Kong, Korea, and Taiwan. The prevalence of erythromycin resistance was also very high in Vietnam (92.1%), Taiwan (86%), Korea (80.6%), Hong Kong (76.8%), and China (73.9%). The MIC(90)s of erythromycin were >32 mg/liter among isolates from Korea, Vietnam, China, Taiwan, Singapore, Malaysia, and Hong Kong. Isolates from Hong Kong showed the highest rate of ciprofloxacin resistance (11.8%), followed by isolates from Sri Lanka (9.5%), the Philippines (9.1%), and Korea (6.5%). Multilocus sequence typing showed that the spread of the Taiwan(19F) clone and the Spain(23F) clone could be one of the major reasons for the rapid increases in antimicrobial resistance among S. pneumoniae isolates in Asia. Data from the multinational surveillance study clearly documented distinctive increases in the prevalence rates and the levels of antimicrobial resistance among S. pneumoniae isolates in many Asian countries, which are among the highest in the world published to date.

Matched MeSH terms: Streptococcus pneumoniae/drug effects*
Macrolide resistance and genotypic characterization of Streptococcus pneumoniae in Asian countries: a study of the Asian Network for Surveillance of Resistant Pathogens (ANSORP)

Song JH, Chang HH, Suh JY, Ko KS, Jung SI, Oh WS, et al.

J Antimicrob Chemother, 2004 Mar;53(3):457-63.
PMID: 14963068

To characterize mechanisms of macrolide resistance among Streptococcus pneumoniae from 10 Asian countries during 1998-2001.

Matched MeSH terms: Streptococcus pneumoniae/drug effects*
In-vitro susceptibilities of Streptococcus pneumoniae strains isolated in Malaysia to six antibiotics

Rohani MY, Parasakthi N, Raudzah A, Yasim MY

J Antimicrob Chemother, 1999 Dec;44(6):852-3.
PMID: 10590295
Matched MeSH terms: Streptococcus pneumoniae/drug effects*
Spread of drug-resistant Streptococcus pneumoniae in Asian countries: Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study

Song JH, Lee NY, Ichiyama S, Yoshida R, Hirakata Y, Fu W, et al.

Clin Infect Dis, 1999 Jun;28(6):1206-11.
PMID: 10451154

Antimicrobial susceptibility of 996 isolates of Streptococcus pneumoniae from clinical specimens was investigated in 11 Asian countries from September 1996 to June 1997. Korea had the greatest frequency of nonsusceptible strains to penicillin with 79.7%, followed by Japan (65.3%), Vietnam (60.8%), Thailand (57.9%), Sri Lanka (41.2%), Taiwan (38.7%), Singapore (23.1%), Indonesia (21.0%), China (9.8%), Malaysia (9.0%), and India (3.8%). Serotypes 23F and 19F were the most common. Pulsed-field gel electrophoresis (PFGE) of 154 isolates from Asian countries showed several major PFGE patterns. The serotype 23F Spanish clone shared the same PFGE pattern with strains from Korea, Japan, Singapore, Taiwan, Thailand, and Malaysia. Fingerprinting analysis of pbp1a, pbp2x, and pbp2b genes of 12 strains from six countries also showed identical fingerprints of penicillin-binding protein genes in most strains. These data suggest the possible introduction and spread of international epidemic clones into Asian countries and the increasing problems of pneumococcal drug resistance in Asian countries for the first time.

Matched MeSH terms: Streptococcus pneumoniae/drug effects*

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