Penicillin susceptibility and molecular characteristics of clinical isolates of Streptococcus pneumoniae at the University of Malaya Medical Center, Kuala Lumpur, Malaysia.
OBJECTIVE
To determine the prevalence of penicillin resistance and molecular characteristics of pneumococcal isolates at the University of Malaya Medical Center.


METHODS
From March 1999 to July 2000, 100 clinical isolates of Streptococcus pneumoniae were obtained from 93 patients of various ages and from various body sites. The minimum inhibitory concentrations (MICs) for penicillin and ceftriaxone were determined by E test, and results were interpreted according to guidelines recommended by the National Committee for Clinical Laboratory Standards (NCCLS). Fifty isolates were further serotyped, and analyzed by pulsed-field gel electrophoresis (PFGE) and polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) of the penicillin-binding protein (pbp) 2b and 2x genes.


RESULTS
The majority of the isolates were from respiratory sites. Thirty-one isolates showed decreased susceptibility to penicillin (PRSP), and many of these also showed decreased susceptibility to ceftriaxone. Twelve serogroup/types (SGTs) were present, with 19F being the most common. PFGE analysis identified two dominant profiles, consisting mainly of PRSPs that had common serotypes (19F) and pbp gene patterns within their respective groups, although PCR-RFLP analysis showed different patterns of pbp genes among the PRSPs as compared to penicillin-susceptible strains, which had a uniform pattern.


CONCLUSIONS
PRSPs were genetically related as shown by PFGE and serotype. The consistency of pbp gene patterns, observed among many of the PRSPs within their respective PFGE profiles, supported their relatedness as established by PFGE.
Desa
Mohd Nasir-Mohd
MN
Department of Clinical Laboratory Science, Faculty of Medicine and Health Science, Universiti Putra Malaysia, Malaysia.
Lin
Thong Kwai
TK
Yasin
Rohani Md
RM
Parasakthi
Navaratnam
N
D000046:Academic Medical Centers; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D002443:Ceftriaxone / Q000494:pharmacology; D016521:Electrophoresis, Gel, Pulsed-Field; D006602:Hexosyltransferases / Q000235:genetics; D006801:Humans; D008296:Malaysia / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics; D010403:Penicillin Resistance; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000494:pharmacology*; D010458:Peptidyl Transferases / Q000235:genetics; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010406:Penicillins; C072223:PBP 2x protein, Streptococcus; D002443:Ceftriaxone; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase