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Emergence of multiply resistant pneumococci
Abstract:
Multiple antimicrobial resistance in pneumococci was detected in Johannesburg in July, 1977, and prompted an investigation of the prevalence of resistant strains in two hospitals. Carriers of Types 6A and 19A penicillin-resistant pneumococci, resistant to antibiotic concentrations ranging between 0.12 and 4 microgram per milliliter were found in 29 per cent of 543 pediatric patients and 2 per cent of 434 hospital staff members. Multiply resistant Type 19A strains, resistant to beta-lactam antibiotics, erythromycin, clindamycin, tetracycline and chloramphenicol, were isolated from 128 carriers, and were responsible for bacteremia in four patients. Isolates from 40 other carriers were resistant to penicillin alone or to penicillin and chloramphenicol or to penicillin, chloramphenicol and tetracycline. Pneumococci can be screened for penicillin resistance with a modified Kirby--Bauer technic; the strains with zones of less than 35 mm around 6-microgram penicillin disks or less than 25 mm around 5-microgram methicillin disks should be tested for sensitivity to penicillin by measurements of minimum inhibitory concentration.
Insights
Multiple antimicrobial resistance in Streptococcus pneumoniae was found in Johannesburg. Penicillin-resistant strains were prevalent in pediatric patients and hospital staff, necessitating further investigation and screening methods.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Multiple antimicrobial resistance in Streptococcus pneumoniae (pneumococci) was identified in Johannesburg in July 1977.
- This discovery prompted an investigation into the prevalence of resistant strains within hospital settings.
Purpose of the Study:
- To determine the prevalence of penicillin-resistant pneumococcal strains among pediatric patients and hospital staff in two Johannesburg hospitals.
- To characterize the antimicrobial resistance patterns of isolated pneumococcal strains.
Main Methods:
- A survey was conducted on 543 pediatric patients and 434 hospital staff members.
- Modified Kirby-Bauer technique and minimum inhibitory concentration measurements were used to screen and confirm penicillin resistance.
Main Results:
- Penicillin-resistant pneumococci (Types 6A and 19A) were found in 29% of pediatric patients and 2% of hospital staff.
- Multiply resistant Type 19A strains, resistant to multiple antibiotics including beta-lactams, erythromycin, clindamycin, tetracycline, and chloramphenicol, were isolated from 128 carriers and caused bacteremia in four patients.
- Other isolates showed resistance to penicillin alone, or in combination with chloramphenicol and/or tetracycline.
Conclusions:
- Penicillin-resistant pneumococci, including multiply resistant strains, were prevalent in the studied population in Johannesburg.
- The findings highlight the need for effective screening methods, such as the modified Kirby-Bauer technique, for detecting penicillin resistance in pneumococci.