Analysis of Increasing Antibiotic Resistance of Klebsiella pneumoniae Relative to Changes in Chemotherapy

Abstract

Three antibiotic-resistant strains of Klebsiella pneumoniae responsible for outbreaks of systemic infection in a hospital nursery were analyzed. Each organism emerged after prolonged use of a drug to which it was resistant. The first strain (RO16) produced neomycin phosphotransferase and contained three plasmids with molecular weights of 24, 25, and 30 X 10(6) daltons, respectively. Resistance to ampicillin, carbenicillin, neomycin, and kanamycin was transferred by conjugation at a frequency of 10(-6). The second strain of K. pneumoniae (RO106) produced gentamicin adenyltransferase and maintained aminoglycoside resistance only when propagated in antibiotic-containing medium. DNA analyses revealed eight species of plasmid DNA: one species with a molecular weight of 70 X 10(6) daltons apparently accounted for conjugal transfer of resistance to ampicillin, carbenicillin, chloramphenicol, and streptomycin. The third strain (RO180) was resistant primarily to colistin and lacked plasmids. Control of the outbreak due to this strain was achieved by aminoglycoside therapy.

Use of plasmid profiles in epidemiologic surveillance of disease outbreaks and in tracing the transmission of antibiotic resistance

“…It may be necessary sometimes to add the appropriate antibiotics to the growth media to maintain plasmids carrying antibiotic resistance genes (147). It is important to remember that changes in plasmid content may also occur in vivo (47,68,114,127,139,173).…”

Klebsiella neonatal injections: mechanism of broadening aminoglycoside resistance

“…Despite antibiotic therapy, drug-resistant K. pneumoniae strains can colonize the intestines and nasopharynx (2, 8,24,26) and invade tissues and blood, causing lethal or potentially lethal infections (13,17,21,25). We report here the characteristics of nine strains of K. pneumoniae isolated from an outbreak ofinfection and compare the properties of these strains with those of other strains previously studied (23) Antibiotic susceptibility testing and transfer ofresistance. The susceptibilities ofeach isolate were determined by measuring the minimal inhibitory concentrations (MICs) of antibiotics in tryptic soy broth (TSB) (Difco Laboratories, Detroit, Mich.) (23).…”

“…We report here the characteristics of nine strains of K. pneumoniae isolated from an outbreak ofinfection and compare the properties of these strains with those of other strains previously studied (23) Antibiotic susceptibility testing and transfer ofresistance. The susceptibilities ofeach isolate were determined by measuring the minimal inhibitory concentrations (MICs) of antibiotics in tryptic soy broth (TSB) (Difco Laboratories, Detroit, Mich.) (23). The abilities of resistant strains to transfer specific resistance traits were determined by cocultivating isolates with a naladixic acid-resistant recipient strain of Escherichia coli, as previously described (23).…”

“…The broadening of resistance was accompanied by reduced uptake of radioactively labeled streptomycin and gentamicin. The relationship between aminoglycoside resistance and reduced drug transport in the absence of any enzymatic modification is discussed.The occurrence of drug-resistant Klebsiella pneumoniae as a cause of life-threatening disease in intensive care nurseries (1,10,16,17,23) remains a challenge in the management of this type ofselected patient population. Despite antibiotic therapy, drug-resistant K. pneumoniae strains can colonize the intestines and nasopharynx (2,8,24,26) and invade tissues and blood, causing lethal or potentially lethal infections (13,17,21,25).…”

“…The susceptibilities ofeach isolate were determined by measuring the minimal inhibitory concentrations (MICs) of antibiotics in tryptic soy broth (TSB) (Difco Laboratories, Detroit, Mich.) (23). The abilities of resistant strains to transfer specific resistance traits were determined by cocultivating isolates with a naladixic acid-resistant recipient strain of Escherichia coli, as previously described (23).…”