DETERMINATION OF ERYTHROMYCIN AND PENICILLIN RESISTANCE GENES IN STREPTOCOCCUS PNEUMONIAE FROM PATIENTS ATTENDING SELECTED HOSPITALS IN KADUNA STATE, NIGERIA
DETERMINATION OF ERYTHROMYCIN AND PENICILLIN RESISTANCE GENES IN STREPTOCOCCUS PNEUMONIAE FROM PATIENTS ATTENDING SELECTED HOSPITALS IN KADUNA STATE, NIGERIA
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Date
2019-06
Authors
LUSA, Haruna Yadock
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Abstract
Streptococcus pneumoniae (Pneumococcus) is both an aggressive pathogen and a normal flora
of the human microbiome with an array of over 90 serotypes.Penicillin-resistant S.
pneumoniae (PRP) and Erythromycin resistant Pneumococci (ERP) has emerged as a
worldwide problem. S. pneumoniae develops penicillin resistance through recombination with
other PRP strains or closely related streptococcal species that alter its penicillin binding protein
(PbP) genes pbp1a, pbp2b, and pbp2x. These altered PbP gene sequences of PRP differ greatly
within the PRP subset and from the sequences of penicillin-susceptible S.pneumoniae
(PSSP),whileresistanceto macrolides in S.pneumoniae arises primarily due to macrolide
resistant Genes (MRGs) including; erythromycin ribose methyltransferase encoded by ermB or
an efflux system leading to selective efflux of 14 and15 membered macrolides encoded by
mef(A).Erythromycin ribose methyltransferase (ermB) typically confers high level resistance to
macrolides, lincosamides and streptogramin B (MLSB phenotype) whereas mef A confers low le
vel resistance to macrolides. The study aimed to detect streptococcus pneumoniae strains with
erythromycin and penicillin resistance genes. A facility based cross sectional study with 450
patients attending selected hospitals in Kaduna State. The enrolled patients were selected by
systematic random sampling presenting with clinically suspected respiratory tract infections
(RTIs). Two hundred and thirty-seven (52.7%) of the subjects were males and 213(47.3%)
were females aged between 10- 70 years with symptoms of respiratory tract infections. Two
hundred and seven (46.0%) of the samples yielded positive growth of which 41(9.1%) were
Streptococcus pneumoniae isolated in 5% blood agar in the presence of 5% CO2,,morphology,
identified with bile solubility, optochin and antibiotic susceptibilities. MIC determination was
done with E-test for penicillin and erythromycin while molecular determination was done for
serotypes macrolide and penicillin resistance genes by PCR.
Incidence of 20.5% Penicillin resistant pneumococci (PRP) and 29.4% Erythromycin resistant
pneumococci (ERP) were established among the elderly patients age ≥ 50 years. Economic
status of the patients had a significant relationship to Penicillin and Erythromycin resistance
(P=0.0004**) determined by disc diffusion technique. Thirty-one (75.6%) of the Pneumococcal
isolates (n=41) were penicillin non-susceptible pneumococci (PNSP)[MICs 1.0-15.5μg/mL;
MIC50=8.0μg/mL) and 31(75.6%) were erythromycin non-susceptible pneumococci(ENSP)
[MICs 0.12-6.0μg/mL;MIC50=0.90μg/mL]determined by E-Test methodology.
Four pneumococcal serotypes were detected in the study area: 3(33.3%), 13(33.3%),
20(16.7%), 23F (16.7%) by conventional PCR serotyping strategy. PCR assay and Agar-gel
electrophoresis for the simultaneous detection of lyt A, Penicillin resistance genes (PRGs:
PbP1a, 2b, 2x) and Macrolide resistance genes (MRGs: ermB and Mef A) was carried out. The
results show 3 of the pneumococcal strains harbor mutations in PbP1a and PbP 2x; six of the
strains express ermB and mefA genes. This study shows that pneumococcal drug resistance in
the area is predominantly mediated by ermB and mefA genes with serotypes 3 and 13 having
the highest frequency among the isolates suggesting the use of more specific gene targets may
in the near future solve the problem of inaccurate identification of pneumococcal infections of
the lower respiratory tract. The finding suggests the use of more specific gene targets in the
near future may solve the problem of inaccurate identification of pneumococcal infections of
the lower respiratory tract. This study also highlights the danger in empirical use of these
groups of antibiotics. Our facilities must be enforced to put in place policies that will guarantee
protection and safety of patients, their relatives and heath personnel.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES
AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT OF THE
REQUIREMENTS FOR THE AWARD OF DOCTOR OF PHYLOSOPHY DEGREE (Ph.D.)
IN MEDICAL MICROBIOLOGY
DEPARTMENT OF MICROBIOLOGY,
FACULTY OF LIFE SCIENCES,
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
Keywords
ERYTHROMYCIN,, PENICILLIN RESISTANCE GENES,, STREPTOCOCCUS PNEUMONIAE,, PATIENTS,, KADUNA STATE,, NIGERIA.