Spread of R-plasmids among Escherichia coli causing urinary tract infections

Abstract

The incidence of multiple-antibiotic resistance among Escherichia coli isolated from urinary tract infections at Charing Cross Hospital, London, increased over the last 10 years, and its distribution was related to 0-type. Among strains of the eight 0-types most frequently causing such infections at this hospital, 04, 09, and 018 had a high incidence of multiple resistance (35, 22, and 19%, respectively); 02 and 06 had an intermediate incidence (14 and 11'1c', respectively); and 07, 01, and 075 had a low incidence (8,6, and <3,c respectively). This nonrandom distribution appears to be a consequence of unequal plasmid recipient ability. After overnight mating with antibiotic-resistant donors, R-plasmid infection frequencies among antibiotic-sensitive urinary tract isolates differed by up to 105_fold, and such differences were correlated with the variation in the incidence of antibiotic resistance among the 0-types. The inherent differences in the ability to achieve significant R-plasmid spread, which appear to be determined by the host, not the plasmid, may be compounded in some cases by the inhibition of potential mating partners by colicin production.The distribution of antibiotic resistance (R) plasmids throughout Escherichia coli populations is not random. A study of E. coli isolated from human feces (9) has demonstrated that strains of 0-antigen types 08, 09, and 0101 occur at a far higher frequency among antibioticresistant isolates (whether shown to carry Rplasmids or not) than among isolates that are antibiotic susceptible. These 0-types are also found to be prevalent among antibiotic-resistant strains isolated from calf feces. A further study has shown that a difference also exists between the 0-types common among the antibiotic-susceptible and -resistant populations of E. coli causing urinary tract infections; 0-types 04, 08, 09, 017, and 018 occur at a relatively high frequency in the R-plasmid-bearing group (16).The majority of urinary tract infections are caused by the predominant 0-type in the patient's own feces at the time of infection (7, 18), but the proportion of infections caused by antibiotic-resistant strains could be affected by such factors as relative colonization and survival ability in the urinary tract and chemotherapeutic practice. Among the various 0-types, colonization and survival ability might be affected to differing degrees by the carriage of R-plasmids.Whether R-plasmid distribution among urinary tract E. coli is indeed determined by such t

The rise and fall of Escherichia coli O 15 in a London Teaching Hospital

“…All isolates were identified by standard biochemical tests3 or by API 20E (API-bioMerieux, Basingstoke). 0serogrouping was done as described previously4 with antisera against 14 of the most common 0-serogroups (1,2,4,5,7,8,9,11,15,17,18,25,75). Antibioticsensitivities were determined by the Stokes method on DST agar (Oxoid; CM 261) with Oxoid disks containing (pg) ampicillin 10, chloramphenicol 10, streptomycin 10, sulphamethoxazole 25, tetracycline 10 and trimethoprim 1.25 and with E. coli NCTC 10418 as control; isolates resistant to all six antibiotics will be referred to as 'multiresistant'.…”

Urinary F plasmids reduce permissivity to coliphage infection

“…Extrapolating from our results and what we know of other niches, we can estimate that F plasmids are widespread in urinary E. coli 42, 100, 101 . We propose a scenario that parallels how antibiotic use can select for bacteria hosting plasmids with antibiotic resistance genes 45, 102, 103 . Phage predation in the urinary tract may drive the transmission and persistence of anti-phage plasmids and, by extension, the genes linked in the plasmid, such as antibiotic resistance and virulence genes.…”

Characterizing Plasmids in Bacteria Species Relevant to Urinary Health

“…The bacterial urinary microbiome (urobiome) includes not just the sequence of a bacteria’s chromosome but also mobile genetic elements, such as prophages and plasmids ( 10 – 12 ). Plasmids can serve as transmissible reservoirs for clinically relevant traits, such as antibiotic resistance, virulence, and fitness genes ( 13 – 15 ). Plasmids can be genetically heterogenous; therefore, conserved replicon genes such as those involved in replication ( rep ) or incompatibility ( inc ) are used for profiling ( 16 – 19 ).…”