High‐Level Tetracycline‐Resistant<i>Neisseria gonorrhoeae</i>in Ontario, Canada—Investigation of a Cluster of Isolates, Showing Chromosomally Mediated Resistance to Penicillin Combined with Plasmid‐Mediated Resistance to Tetracycline

Harnett, N; Brown, Stephen C.; Terro, R; Krishnan, C.; Pauzé, M; Yeung, Kwok-Him

doi:10.1086/514122

Cited by 7 publications

(7 citation statements)

References 27 publications

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“…On the basis of the criteria defined by Tenover et al (27), a single genetic event such as a point mutation in the posttreatment isolate could be reflected as a difference of one to three bands. PFGE pattern variation between the posttreatment isolate and the original isolate was previously reported by Harnett et al (8). In their report the interval between the recovery of the two isolates was 4 months.…”

Section: Discussionsupporting

confidence: 58%

Molecular Basis of High-Level Ciprofloxacin Resistance in Neisseria gonorrhoeae Strains Isolated in Denmark from 1995 to 1998

Lind

2001

Antimicrob Agents Chemother

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In Denmark surveillance of the in vitro susceptibility to ciprofloxacin of Neisseria gonorrhoeae was established in 1990. The proportion of N. gonorrhoeae strains with decreased susceptibility or resistance to ciprofloxacin (MIC > 0.06 g/ml) was low (0.3 to 2.3%) up to 1995. Between 1995 and 1998 the rate of lesssusceptible and resistant strains rose from 6.9 to 13.2%. Among ciprofloxacin-resistant strains (MIC > 1 g/ml), 81% were highly resistant (MIC > 4 g/ml). Thirty-five N. gonorrhoeae strains (40 isolates) for which ciprofloxacin MICs were 4 to 32 g/ml were investigated for the frequency and patterns of mutations within the gyrA and parC genes. The quinolone resistance-determining regions of the gyrA and parC genes were amplified by PCR, and the amplicons were directly sequenced. Alterations at Ser-91 and Asp-95 in GyrA and a single or double alteration in ParC were identified in 32 strains (91%). Ser-91-to-Phe and Asp-95-to-Gly alterations in GyrA were detected in 28 strains (80%). The most common ParC alteration, Asp-86 to Asn, was found in 19 strains (54%). The strains were analyzed for genetic relationship by pulsed-field gel electrophoresis (PFGE). The analysis showed that nine strains with the same mutation pattern in the gyrA and parC genes, originating from different geographical areas over 3 years, had the same PFGE patterns after SpeI as well as NheI digestion (only one strain with one band difference in the NheI pattern), suggesting that a resistant clone had spread worldwide. The results from this study strongly suggest that double gyrA mutations plus a parC mutation(s) play an important role in the development of high-level fluoroquinolone resistance in N. gonorrhoeae.

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Section: Discussionsupporting

confidence: 58%

Molecular Basis of High-Level Ciprofloxacin Resistance in Neisseria gonorrhoeae Strains Isolated in Denmark from 1995 to 1998

Lind

2001

Antimicrob Agents Chemother

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“…Interestingly, in a 1994 study from Ontario in which a subset of 99 (1.7%) of the 5,789 isolates from Ontario in the present report were characterized by A/S/P and PFGE analysis, a cluster of 82 strains of A/S class NR/ IB-1 with identical or closely related PFGE profiles was identified, and the other 17 strains displayed eight different A/S classes and 12 different PFGE profiles. 13 Our present study un-GRECO ET AL. 358 derscores the importance of having an adequate sample size when A/S class is being used to define different populations of strains from surveillance studies; otherwise, the results of a small, random sample size might lead to an inaccurate portrayal of the strain type distribution.…”

Section: Discussionmentioning

confidence: 62%

Molecular Epidemiology ofNeisseria gonorrheaeIsolates with Plasmid-Mediated Tetracycline Resistance in Canada: Temporal and Geographical Trends (1986-1997)

Greco

Catana

et al. 2003

Microbial Drug Resistance

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Plasmid-mediated resistance to tetracycline in Neisseria gonorrhoeae (TRNG) isolates is caused by the acquisition of a 25.2-MDa conjugative, tetM-containing plasmid (TetM plasmid). The presence of the TetM plasmid is the leading cause of gonococcal resistance to tetracycline in most countries. Between 1986 and 1997, 6,306 TRNG isolates were isolated in different Canadian provincial laboratories and subsequently submitted to the national laboratory for further strain characterization. Because nonculture-based identification of N. gonorrhoeae was more widely used after 1995, this snapshot of the molecular epidemiology of TRNG in Canada, which is only possible if bacteria are cultured, represents a comprehensive data baseline that may no longer be achievable. Temporal trends indicate that TRNG isolations peaked in 1994 (18.9% of isolates tested). Antimicrobial susceptibilities (MIC) to tetracycline and penicillin were determined for 4,064 TRNG isolated between 1986 and 1994. The MICs of TRNG isolates ranged from 16 microg/ml to 32 microg/ml of tetracycline, although one isolate had an MIC of 8 microg/ml and the MICs of four isolates were 2 microg/ml. Penicillinase-producing TRNG (i.e., PP/TRNG) comprised 34.1% of all TRNG (n = 1,386) and 52 TRNG isolates exhibited chromosomal resistance to penicillin. Most of the PP/TRNG (94.1%) carried Africa type (3.2 MDa) beta-lactamase-producing plasmids; only 76 (5.5%) PP/TRNG carried Asia type (4.4 MDa) penicillinase-producing plasmids and three isolates carried Toronto type (3.05 MDa) plasmids. TRNG isolates were also retrospectively typed by auxotype (A), serovar (S), and plasmid (P) content analysis. Eleven auxotype/serovar (A/S) groups comprised the majority (93%) of 4,064 typed TRNG isolates with A/S classes NR/IB-2, NR/IB-3, and NR/IB-1 accounting for 75.1% of the strains characterized. Classification of 670 TRNG for tetM type demonstrated that the Dutch (n = 531) type TetM plasmids predominated over the American (n = 139) type TetM plasmids.

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“…However the main TRNG serovars vary considerably, with 1A8 predominating in Portugal (77%) 8 , Malaysia (38%) 15 , and Thailand (25%) 16 , 1B2 predominating in Canada (65%) 17 , and 1A6 predominating in Zaire (77%) 19 .…”

Section: Discussionmentioning

confidence: 99%

Subtyping of High-Level Plasmid-Mediated Tetracycline Resistant Neisseria Gonorrhoeae Isolated in Scotland between 1992 and 1998

et al. 1999

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Tetracycline resistant Neisseria gonorrhoeae (TRNG) contain a 25.2 MDa TetM plasmid encoding a 68 KDa cytoplasmic protein which confers high-level tetracycline resistance. The aim of this study was to subtype all TRNG isolated in Scotland between 1992 and 1998. Subtyping was performed by a polymerase chain reaction (PCR) assay which characterizes the TetM plasmid as either the Dutch variant (443 base pair product) or the American variant (777 base pair product). Of the 78 TRNG isolates, 35 were the American variant and 43 were the Dutch variant. TRNG were distributed amongst 30 serovar/auxotype classes, the most common being 1A6/NR (11.5%), 1A6/P (14.1%) and 1B4/NR (14.1%). The country where infection was acquired was known for 36 of the 46 TRNG strains isolated between 1996 and 1998. All infections acquired in Asia and South America were the Dutch variant whereas all infections acquired in Africa were the American variant. A penicillinase plasmid was present in 66% (23/35) of the American variant TRNG compared with 51% (22/43) of the Dutch variant: the 3.2 MDa penicillinase plasmid was found in 87% of the American variant TRNG whereas the 4.4 MDa penicillinase plasmid was found in 68% of the Dutch variant TRNG. We conclude that subtyping of TRNG by PCR is a useful tool in studying the epidemiology of gonococcal infection due to plasmid-mediated resistant isolates.

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High‐Level Tetracycline‐ResistantNeisseria gonorrhoeaein Ontario, Canada—Investigation of a Cluster of Isolates, Showing Chromosomally Mediated Resistance to Penicillin Combined with Plasmid‐Mediated Resistance to Tetracycline

Cited by 7 publications

References 27 publications

Molecular Basis of High-Level Ciprofloxacin Resistance in Neisseria gonorrhoeae Strains Isolated in Denmark from 1995 to 1998

Molecular Basis of High-Level Ciprofloxacin Resistance in Neisseria gonorrhoeae Strains Isolated in Denmark from 1995 to 1998

Molecular Epidemiology ofNeisseria gonorrheaeIsolates with Plasmid-Mediated Tetracycline Resistance in Canada: Temporal and Geographical Trends (1986-1997)

Subtyping of High-Level Plasmid-Mediated Tetracycline Resistant Neisseria Gonorrhoeae Isolated in Scotland between 1992 and 1998

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