novobiocin and Cross-Infection

Several methods were used to type 64 clinical isolates of coagulase-negative staphylococci (CNS) derived from hospitals in Morocco. The clinical isolates originated principally from blood cultures and wound sources. These isolates provided the opportunity to substantially compare the proficiency of developing molecular techniques with conventional phenotypic tests for use in the identification of clinical staphylococci. The following molecular methods were examined: Utility ribotyping analysis (Ribotyping); PCR analysis performed with 16S-23S ribosomal-DNA intergenic spacer (ITS-PCR); PCR-based random amplified polymorphic DNA (RAPD). The results obtained by the molecular techniques were contrasted to those of conventional phenotypic tests. Conventional phenotypic tests allowed the outright recognition of the majority of isolates (50/64). These 50 isolates were subdivided into 33 novobiocin-susceptible and 17 novobiocin-resistant strains of CNS. However, 2 other novobiocin-susceptible and 12 other novobiocin-resistant isolates remained unclassified by these tests. There was a good agreement between the conventional phenotypic tests and RAPD for the 33 novobiocin-susceptible isolates. But, the RAPD technique permitted the assignment of the two unidentified novobiocin-susceptible isolates to the Staphylococcus hominis species. A complete correlation was obtained between the three molecular tools for recognition of the 12 novobiocin-resistant isolates that were not identified by phenotypic typing; these were in fact identified as 5 Staphylococcus cohnii and 4 Staphylococcus equorum. Three isolates remained unidentified by all three systems of molecular techniques.

Topics: Bacterial Proteins; Bacterial Typing Techniques; Coagulase; Cross Infection; DNA, Bacterial; DNA, Ribosomal; DNA, Ribosomal Spacer; Drug Resistance, Microbial; Humans; Morocco; Novobiocin; Polymerase Chain Reaction; Random Amplified Polymorphic DNA Technique; Species Specificity; Staphylococcal Infections; Staphylococcus

Following implementation of special measures to control a nosocomial outbreak of methicillin-resistant Staphylococcus aureus (MRSA), we used immunoblot typing in conjunction with antimicrobial susceptibility testing to investigate the epidemiology of this event and to determine whether this outbreak represented the failure of infection control measures to limit the spread of previously endemic MRSA strains or the introduction of a new strain of MRSA.. Isolates of MRSA recovered from hospitalized patients were initially categorized on the basis of antimicrobial susceptibility results. Organisms susceptible to ciprofloxacin and/or trimethoprim/sulfamethoxazole were recovered from patients at a relatively constant rate prior to December 1988 and were categorized as endemic isolates. Subsequently, there was an outbreak due to organisms resistant to both of these antibiotics; these were therefore categorized as outbreak isolates. Isolates were later characterized by immunoblot typing. Prior to this analysis, isolates were given code numbers so that clinical and epidemiologic data as well as resistance patterns were not known until this testing was complete.. Between January 1986 and November 1988, an average of 3.9 patients per month acquired nosocomial MRSA in the Sepulveda Veterans Administration Medical Center. In contrast, from December 1988 to October 1989, 369 MRSA isolates were collected from 125 patients (an average of 11.4 patients per month). Prior to December 1988, all tested nosocomial isolates of MRSA were susceptible to ciprofloxacin and/or to trimethoprim/sulfamethoxazole. In contrast, the outbreak was due to spread of MRSA isolates resistant to these antibiotics. Immunoblot typing of 204 isolates from 98 individuals identified five distinct immunoblot types of which types B and C were by far the most common. Type B was highly associated with outbreak isolates, whereas type C was associated with endemic isolates (p less than 0.001). All sequential isolates from single patients that belonged to different susceptibility categories demonstrated discordant immunoblot types. In contrast, concordant immunoblot types were observed for 25 of 27 sequential isolates that displayed minor variations in antimicrobial resistance. The institution of more stringent infection control measures was followed by the return of nosocomial MRSA acquisition rates to pre-outbreak levels. Although novobiocin and trimethoprim/sulfamethoxazole were extensively used to treat patients harboring outbreak and endemic isolates, respectively, in no instance was the initial MRSA isolate from any patient resistant to novobiocin and only 6% of initial endemic isolates displayed trimethoprim/sulfamethoxazole resistance. A modest, significant increase in the resistance of endemic isolates to various other antimicrobial agents was noted however.. Immunoblot analyses provided strong, corroborative evidence that at least two separate strains of MRSA were present during the outbreak and that a newly introduced strain with a distinctive antimicrobial resistance pattern was primarily responsible for the rapid spread of MRSA during the outbreak. The observation that previously effective infection control measures failed to prevent the nosocomial spread of a newly introduced community-acquired MRSA strain suggests that a single set of control measures may not be equally efficacious against all strains of MRSA. In this regard, previously reported variations in resistance to topical antimicrobials and/or antiseptics, and differences in virulence factors such as colonization potential, invasiveness, and survival on fomites, may warrant further study. Control of the outbreak strain of MRSA in our institution did occur after the implementation of more strenuous isolation procedures.(ABSTRACT TRUNCATED)

Topics: California; Carrier State; Cross Infection; Disease Outbreaks; Evaluation Studies as Topic; Hospitals, Veterans; Humans; Immunoblotting; Incidence; Infection Control; Methicillin Resistance; Microbial Sensitivity Tests; Novobiocin; Occupational Diseases; Organizational Policy; Personnel, Hospital; Prevalence; Seasons; Serotyping; Staphylococcal Infections; Staphylococcus aureus; Trimethoprim Resistance; Trimethoprim, Sulfamethoxazole Drug Combination

Pseudomonas cepacia, considered a phytopathogenic organism for many years, has been shown recently to be widely distributed geographically. The hospital environment has become an important source of this organism but the resistance of Ps. cepacia to most antibiotics has made the treatment of infections a problem. One hundred per cent of the strains tested have proved to be sensitive to the sulphonamides and to novobiocin, 93.0% to the combination of trimethoprim and sulfamethoxazole (co-trimoxazole); 85.2% to minocycline; 77.8% to chloramphenicol and dibekacin and 44.4% to nalidixic acid. One hundred per cent of the strains exhibit resistance to ampicillin, cephalothin, cefamandole, cefoxitin, colistin, cefuroxime, tetracycline and cefazolin; 88.9% to amikacin, tobramycin and sisomycin; 85.2% to carbenicillin. The new beta-lactams, apalcillin, ceftazidime, N-formimidoyl-thienamycin, piperacillin, cefotaxime and azlocillin proved to be the most potent of the molecules tested, inhibiting 90% of the strains, at concentrations of 4, 8, 8, 8, 32 and 16 mg/l and 100% of the strains at 8, 16, 16, 32, 32 and 64 mg/l, respectively. In contrast to the usual sensitivity patterns of Pseudomonas spp, Ps. cepacia has been shown to be resistant to colistin, cefsulodin and the aminoglycosides. However, unlike Ps. aeruginosa, Ps. cepacia has been shown, by the dilution method, to be sensitive to co-trimoxazole, 92.3% of the strains being inhibited by 16 mg/l.

Topics: Anti-Bacterial Agents; Ceftazidime; Cross Infection; Drug Combinations; Drug Resistance, Microbial; Humans; Microbial Sensitivity Tests; Minocycline; Novobiocin; Pseudomonas; Pseudomonas Infections; Species Specificity; Sulfamethoxazole; Trimethoprim; Trimethoprim, Sulfamethoxazole Drug Combination

The susceptibility of 83 non-pigmented Serratia marcescens strains was determined by an agar dilution technique. They originated from miscellaneous pathological specimens submitted to the diagnostic laboratory during a nosocomial infection outbreak in 1974. All strains were completely resistant to 128 mug/ml of cephalothin, colistin sulphomethate, lincomycin and penicillin G. They were also resistant to clinically attainable concentrations of ampicillin, chloramphenicol, erythromycin, novobiocin and tetracycline. With regard to drugs with some activity 84% of the strains were susceptible to nalidixic acid, 48% to sulphamethoxazole, 57% to streptomycin, 60% to kanamycin, 61% to gentamicin, 85% to co-trimoxazole and 100% to amikacin. Environmental strains isolated from the infected units were strikingly more sensitive than the patient strains.

Topics: Amikacin; Ampicillin; Anti-Bacterial Agents; Carbenicillin; Chloramphenicol; Cross Infection; Erythromycin; Gentamicins; Humans; Kanamycin; Microbial Sensitivity Tests; Nalidixic Acid; Novobiocin; Rifampin; Serratia marcescens; Sputum; Streptomycin; Sulfamethoxazole; Tetracycline; Trimethoprim; Urine; Wound Infection

Topics: Anti-Bacterial Agents; Cloxacillin; Cross Infection; DNA, Bacterial; Extrachromosomal Inheritance; Fusidic Acid; Genes; Genetic Linkage; Humans; Methicillin; Novobiocin; Penicillin Resistance; Penicillinase; Skin; Staphylococcal Infections; Staphylococcus; Streptomycin; Transduction, Genetic; Transformation, Genetic; Trimethoprim

Topics: Adult; Ampicillin; Anti-Bacterial Agents; Bacteria; Cephalothin; Chloramphenicol; Cross Infection; Erythromycin; Escherichia coli Infections; Female; Gentamicins; Humans; Kanamycin; Klebsiella Infections; Lincomycin; Male; Microbial Sensitivity Tests; Novobiocin; Oxacillin; Penicillin G; Penicillin Resistance; Proteus Infections; Streptomycin; Sulfates; Tetracycline

Topics: Bacitracin; Burns; Chloramphenicol; Cross Infection; Erythromycin; Fusidic Acid; Humans; Methicillin; Microbial Sensitivity Tests; Neomycin; Nose; Novobiocin; Penicillin Resistance; Penicillins; Staphylococcal Infections; Staphylococcus; Streptomycin; Tetracycline

Topics: Ampicillin; Anti-Bacterial Agents; Bacteriophage Typing; Chloramphenicol; Cloxacillin; Cross Infection; Erythromycin; Hospitals; Humans; Methicillin; Microbial Sensitivity Tests; Novobiocin; Paratyphoid Fever; Penicillin G; Penicillin Resistance; Penicillins; Sepsis; Staphylococcal Infections; Staphylococcus

Topics: Anti-Bacterial Agents; Bacitracin; Bacteriophage Typing; Boston; Cephaloridine; Chloramphenicol; Cross Infection; Drug Resistance, Microbial; Erythromycin; Humans; Kanamycin; Lincomycin; Microbial Sensitivity Tests; Novobiocin; Penicillin Resistance; Staphylococcal Infections; Staphylococcus; Tetracycline; Vancomycin

Topics: Animals; Anti-Bacterial Agents; Bacteriophage Typing; Cloxacillin; Cross Infection; Erythromycin; Female; Humans; Infant, Newborn; Methicillin; Mice; Milk, Human; Mouth; Nose; Novobiocin; Oleandomycin; Oxacillin; Oxytetracycline; Penicillin Resistance; Penicillinase; Penicillins; Rabbits; Staphylococcus; Staphylococcus Phages; Streptomycin

Topics: Ampicillin; Bacitracin; Cephalosporins; Chloramphenicol; Cross Infection; Erythromycin; Humans; Infant, Newborn; Infant, Newborn, Diseases; Infant, Premature, Diseases; Methicillin; Novobiocin; Penicillin G; Sepsis; Tetracycline; Troleandomycin; Vancomycin

Topics: Bacteriological Techniques; Cross Infection; England; Fusidic Acid; Hospitals, General; Humans; Methicillin; Methicillin Resistance; Novobiocin; Penicillin Resistance; Staphylococcal Infections; Staphylococcus; Staphylococcus Phages; Statistics as Topic; Streptomycin; Surgical Wound Infection

A survey of Staphylococcus albus urinary infections is reported from a general hospital. The infection followed urethral instrumentation in 75% of the patients, and was usually caused by organisms already present in the urethra. Novobiocin-resistant strains caused infections in four out-patients with no predisposing lesions or instrumentation of the urinary tract.

Topics: Bacteriology; Coagulase; Cross Infection; Drug Resistance, Microbial; Humans; Hydrolases; Male; Novobiocin; Penicillin Resistance; Staphylococcal Infections; Staphylococcus; Staphylococcus epidermidis; Streptomycin; Tetracycline; Urethra; Urinary Catheterization; Urinary Tract Infections

Topics: Anti-Bacterial Agents; Chloramphenicol; Cross Infection; Drug Resistance; Drug Resistance, Microbial; Erythromycin; France; Novobiocin; Oleandomycin; Penicillins; Saints; Spiramycin; Staphylococcal Infections; Staphylococcus aureus; Streptomycin; Tetracycline

Topics: Anti-Bacterial Agents; Chloramphenicol; Cross Infection; Drug Resistance; Drug Resistance, Microbial; Erythromycin; Humans; Novobiocin; Staphylococcal Infections; Staphylococcus aureus; Staphylococcus Phages; Tetracycline