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

Abstract

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.

The prevalence and epidemiology of plasmid-mediated penicillin and tetracycline resistance among Neisseria gonorrhoeae isolates in Guangzhou, China, 2002–2012

“…The results showed various distribution of tet M types, 98.3 % (59/60) American and 0.7 % (1/60) Dutch type in Africa, 40 % (4/10) American and 60 % (6/10) Dutch type in North, Central and South America, 64.3 % (36/56) American and 35.7 % (20/56) Dutch type in the Caribbean, 82 % (248/306) American and 18 % (58/306) Dutch type in Europe, and 100 % (35/35) Dutch type in the Far East [ 25 ]. In addition, Canada also reported that Dutch type tet M gene predominated (79.35 %) from 1986 to 1997 [ 35 ]. In recent years, 24 % (37/154) Dutch and 76 % (117/154) American type were found in South Africa in 2008 [ 34 ].…”

Strain Typing and Antimicrobial Resistance of Fluoroquinolone-Resistant Neisseria gonorrhoeae Causing a California Infection Outbreak

“…When these methods are used in combination with Lip typing and determination of the amino acid alteration patterns in the QRDRs of GyrA and ParC, they provide an additional ability to discriminate strain types. The PFGE technology has also been used to characterize N. gonorrhoeae strains, including QRNG, and is commonly available in many public health laboratories (34,35), although the use of two restriction enzymes, such as NheI and SpeI, would be recommended for surveillance for gonococcal strains (13,20). Ideally, methods for the monitoring of strain types with resistance should be standardized internationally to allow global surveillance, because antimicrobial-resistant N. gonorrhoeae is an international public health threat that needs to be monitored as part of a coordinated control plan (26,33).…”

Increasing Incidence of High-Level Tetracycline-ResistantNeisseria gonorrhoeaedue to Clonal Spread and Foreign Import

“…These changes in the antimicrobial susceptibilities of TRNG isolates were also reported in India by Bala, et al 26 Such changes can result from the horizontal spread of a plasmid bearing the tetM gene to resistant non-TRNG isolates, because plasmids can move between isolates. 27 28 29 This phenomenon may provide a second explanation for the increase in TRNG isolates. However, considering the fact that the selective pressure for tetracycline was very low in Korea since the 1990s, 22 horizontal transfer seems a less likely explanation than the other alternatives.…”