Abstract
BackgroundPenicillinase-producing Neisseria gonorroheae (PPNG) was first isolated in 1976. PPNG strains carrying blaTEM-1 and blaTEM-135 gene have been described in different countries. Recently, a novel blaTEM-220 allele was detected in PPNG isolates carrying Toronto/Rio plasmid. The prevalence and characteristics of TEM-220 strains worldwide are unknown, and therefore, it needs to be studied. The purpose of this study was to detect blaTEM-220 gene in PPNG strains possessing Toronto/Rio plasmid over a period of ten years in Argentina, and to evaluate the proportion of isolates producing non-TEM-220 containing the T539C substitution in the blaTEM allele.MethodsOne hundred and fifty one PPNG isolates carrying Toronto/Rio plasmid were studied between 2002 and 2011. A mismatch amplification mutation assay (MAMA) PCR was used to identify the T539C substitution in the blaTEM allele and a MAMA-PCR protocol was developed to detect the G547A substitution in the blaTEM-220. The reference agar dilution method of the Clinical and Laboratory Standard Institute (CLSI) was used for susceptibility testing to five β-lactams antibiotics, ciprofloxacin, tetracycline and azithromycin. In all TEM-220-producing isolates, the whole blaTEM gene was sequenced and the isolates were typed using N. gonorroheae multiantigen sequence typing (NG-MAST).ResultsMAMA PCR successfully identified the G547A substitution in the blaTEM-220 allele. The proportion of isolates that possessed the blaTEM-220 allele was 2.6 %, and 93.2 % MAMA TEM-220 PCR-negative isolates showed the T539C substitution in the blaTEM gene. No differences in the susceptibility to five beta-lactam antibiotics tested were observed in PPNG isolates TEM-220-producing and PPNG isolates carrying the T539C substitution in the blaTEM gene. All TEM-220 isolates were indistinguishable by NG-MAST.ConclusionThis is the first study which shows the prevalence of blaTEM-220 in N. gonorrhoeae isolates carrying Toronto/Rio plasmid in Argentina. Although the blaTEM-220 allele does not appear to be associated with an extended spectrum beta-lactamase (ESBL) phenotype of resistance, a single nucleotide polymorphism added to the blaTEM-220 or blaTEM containing the T539C substitution could lead to the emergence of ESBL. Thus, it is imperative to investigate in surveillance programs, not only the plasmid type in PPNG isolates and the blaTEM allele associated, but phenotypical characteristics and geographical distribution of isolates.
Highlights
Penicillinase-producing Neisseria gonorroheae (PPNG) was first isolated in 1976
We studied 151 PPNG isolates carrying Toronto/Rio plasmid previously identified as N. gonorrhoeae based on the characteristic colony morphology, Gram staining, oxidase test, superoxol test (30 % hydrogen peroxide), carbohydrate utilization test, and the Phadebact GC Monoclonal Test (MKL Diagnostic AB, Sollentuna, Sweden) [25]
Over the period from 2002 to 2011, 3895 N. gonorrhoeae isolates were submitted from GASSP-AR for antimicrobial susceptibility testing
Summary
Penicillinase-producing Neisseria gonorroheae (PPNG) was first isolated in 1976. PPNG strains carrying blaTEM-1 and blaTEM-135 gene have been described in different countries. The purpose of this study was to detect blaTEM-220 gene in PPNG strains possessing Toronto/Rio plasmid over a period of ten years in Argentina, and to evaluate the proportion of isolates producing non-TEM-220 containing the T539C substitution in the blaTEM allele. Neisseria gonorrhoeae is the etiological agent of the sexually transmitted infection gonorrhea, which remains a major public health issue It represents 88 million of the estimated 448 million new cases of curable sexually transmitted infections that occur globally every year [1]. PPNG strains were reported for the first time in 1976 in the United Kingdom and the United States [8, 9] These strains produce a TEM type β-lactamase, which is carried on several related plasmids. PPNG isolates are highly prevalent in our country and three plasmids types (Asian, African and Toronto/Rio plasmids) have been detected, resulting African and Toronto/Rio the most prevalent
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