Sensitivity of 858 strains of staphylococci to 27 antibiotics

Susceptibility to 27 antimicrobial agents of 858 strains of staphylococci was determined. Tested strains belonged to the following species: S. epidermidis, S. saprophyticus, S. haemolyticus, S. hominis, S. simulans, S. warneri, S. cohnii, S. xylosus and S. intermedius. The antibiotics were: penicillin G, amoxycillin, augmentin, oxacillin, streptomycin, kanamycin, tobramycin, dibekacin, amikacin, gentamicin, sisomycin, netilmicin, doxycycline, minocycline, chloramphenicol, erythromycin, josamycin, clindamycin, pristinamycin, rifampin, fusidic acid, fosfomycin, trimethoprim, sulfamethoxazole, cotrimoxazole, and vancomycin. The ATB system was used, with the criteria for categorization recommended by the Antibiotic Sensitivity Testing Committee. Penicillin-resistance, that was found in all species, was high for hospital-acquired strains (67 to 75%) but also for some other strains (32% for S. simulans). Oxacillin-resistance varied across species (0% for the least prevalent hospital strains, 6% for S. epidermidis and 28% for S. haemolyticus). All strains were susceptible to vancomycin. For some drugs, resistance was a characteristic of the species: resistance to fosfomycin was often found for S. saprophyticus, S. haemolyticus, S. warneri, S. cohnii, and S. capitis; resistance to trimethoprim was common for S. simulans, and S. haemolyticus. S. haemolyticus was the most resistant species, a fact that justifies routine identification of this pathogen in clinical specimens.     

Sensitivity to various antibiotics of spiroplasmas isolated from mosquitoes in France

Spiroplasmas are helical mycoplasmas that play a significant role in plant diseases. They are also found in arthropods that are likely to bite humans, such as ticks and mosquitoes. These arthropods can act as vectors and therefore may be of epidemiologic significance. Furthermore, mainly on the grounds of morphologic evidence, spiroplasmas have been incriminated in the genesis of human Creutzfeld-Jacob disease. We recovered six strains of Spiroplasma sp. from 1927 female mosquitoes. In vitro susceptibility of each strain to the following antibiotics was studied: tetracycline, oxytetracycline, doxycycline, erythromycin, chloramphenicol, rifampin, kanamycin, gentamicin and pefloxacin. Minimal inhibitory concentrations (MICs) were determined by dilution in liquid SP4 medium using microtiter plates. Plates were incubated for 24 to 48 hours at 30 degrees C. The inoculum contained approximately 5 X 10(5) CFU/ml. Each of the six strains was found to be highly susceptible to tetracycline, oxytetracycline, doxycycline, erythromycin, chloramphenicol and pefloxacin (MICs less than or equal to 0.16 microgram/ml, 0.63 microgram/ml, 0.08 microgram/ml, 0.16 microgram/ml and 0.32 microgram/ml respectively). On the opposite, the strains exhibited resistance to rifampin and variable degrees of susceptibility to kanamycin (12.5 micrograms/ml less than MIC less than 50 micrograms/ml) and gentamicin (3.12 micrograms/ml less than MIC less than 50 micrograms/ml). From our results, spiroplasmas seem to have more or less the same susceptibility to antibiotics as mycoplasmas.     

Species identification and susceptibility to 17 antibiotics of coagulase-negative staphylococci isolated from clinical specimens.

A total of 299 isolates of gram-positive, catalase-positive, coagulase-negative cocci were isolated from a variety of specimens collected from patients at a large university hospital, and 281 (94%) were identified as staphylococci by established methods. Using the scheme of Kloos and Schleifer, we determined the species of the coagulase-negative staphylococci. Staphylococcus epidermidis was the cause of all bacteremias and the most commonly isolated species from bone, joint, and wound infections. Staphylococcus haemolyticus was the second most common isolate from wound infections, and Staphylococcus saprophyticus was the most commonly isolated species from urinary tract infections. Antibiograms to 17 antimicrobial agents were performed by a microdilution technique, and the results revealed that S. epidermidis was resistant to a water spectrum of antimicrobial agents than the other species of staphylococci were.     

Identification of nuclease-positive staphylococci isolated from animals

The nuclease-neutralisation test was evaluated as a means of identifying nuclease-positive staphylococci isolated from different animals. The test identified 510 of 520 strains (98%) of staphylococci characterised by biochemical testing.     

Classification of staphylococci isolated from ocular tissues.

A total of 145 strains of Gram-positive, catalase-positive, coagulase-positive, and coagulase-negative cocci isolated from the human eye were classified by the system of Baird-Parker (1966). These belonged to subgroups I, II, IV, and V and showed a wide range of antibiotic sensitivities unrelated to subgroup and category of lesion. The role of coagulase-negative staphylococci in producing postoperative ocular infections has been especially emphasised.     

Inclusion-bearing cells in industrial workers exposed to lead

Histochemical and microscopic studies have shown that a characteristic renal response to lead exposure is the formation of discrete, dense, staining intranuclear inclusion bodies in renal tubular epithelial cells. Cytologic examination of urinary sediment showed that four of 19 (21%) lead workers had exfoliated inclusion-bearing cells of proximal renal tubular origin. These lead-induced inclusion-bearing cells appeared distinctly different from viral-induced inclusions, degenerative or nonspecific intranuclear inclusions seen with tubular necrosis, or macronucleoli seen in reparative renal tubular epithelium. While their presence indicates cytologic evidence of tubular injury, the clinical significance of these cells and their application to medical monitoring is not clearly understood.     

Specific antibodies to methyltetrahydrophthalic anhydride in exposed workers

A group of 145 workers exposed to methyltetrahydrophthalic anhydride (MTHPA) was investigated. They were working in a plant which, since 1983, handled an epoxy resin with MTHPA as a hardener. Specific IgE antibodies (RAST) to a conjugate between MTHPA and human serum albumin (HSA) were statistically significantly increased (P= 0·001; 26 subjects = 18% positive) in the exposed group, compared to a non-exposed control group (n= 33). One positive worker was only exposed for 2 months. Twenty-three exposed subjects were also skin-prick test positive to MTHPA-HSA. The exposed group was divided into three different exposure categories, according to their contact with the epoxy resin. The average exposure levels at the time of the investigation were, in zone 10·085 mg/m³, in zone II0·014 mg/m³, and in zone III 0·010 mg/m³, though the exposure probably had been higher earlier. There was an association between exposure intensity and RAST-positive persons (P= 0·0025, chi-square trend test). Forty-four persons (30%) were smokers, and 16(11%) atopics. No association between sensitization and either atopy or smoking was found. There was an association between exposure intensity and specific IgG antibodies (P= 0·0003, chi-square trend test). Specific IgG₄ antibodies were closely related to specific total IgG antibodies (P= 0·0001). These findings demonstrate that MTHPA is a sensitizing agent at low levels of exposure.     

Pulmonary pathology in workers exposed to nonasbestiform talc

We studied pulmonary tissue from seven men employed in the mining and milling of talc that contained minimal amounts of crystalline silica and asbestiform minerals. The lungs exhibited varying degrees of fibrosis, located either adjacent to the vessels and bronchi or diffusely. Semiquantitative estimations of talc in the lung tissue indicated that the extent of the pulmonary lesions corresponded to its concentration in the tissue. Histopathologic findings were evaluated with regard to duration of occupational exposure and radiographic changes in the chest. In three of the seven workers with exposures of 26, 27, and 27 years chest roentgenographic changes were consistent with pneumoconiosis. The lung tissues from four other patients with exposure histories of four, five, 13, and 19 years exhibited focal and diffuse fibrosis with accumulations of talc, but the chest x-ray films were negative. Crystallographic studies of digestates of lung tissue indicated that the talc contained few mineral impurities. An increase in dust load in the lungs was associated with duration of employment.     

Typing of coagulase-negative staphylococci isolated from foreign body infections

Twenty-six coagulase-negative staphylococci isolated from patients with various foreign body infections were characterised using different typing systems.Staphylococcus epidermidis was the most predominant species found. Phage typability was below 50 % in all strains. The strains showed differences in surface properties — relative hydrophobicity or hydrophilicity — and ability to adhere to polystyrene with subsequent slime production (adherence tube test). Protein and polypeptide profiles as well as plasmid profiles demonstrated the heterogeneity of the strains. Thus, this preliminary study indicates that all coagulase-negative staphylococci of human origin may become involved in foreign body infections.     

Slime-producing properties of coagulase-negative staphylococci isolated from blood cultures

Objective: To evaluate five methods for the determination of slime-producing properties in coagulase-negative staphylococci (CNS).
Methods: One hundred and sixty-two strains of CNS considered as 'contaminants' and 162 strains associated with 'bacteremia' were tested with the tube test with tryptic soy broth, the tube test with brain-heart infusion broth supplemented with 5% sucrose, the Congo red agar method, and the microtiter-plate test with trypan blue and crystal violet, both with tryptic soy broth.
Results: Of the 324 strains tested, 188 were negative and 58 were positive with all methods. The remaining 78 strains were positive with one or more methods.
Conclusions: There was a significant difference ( p <0.001) in slime production between 162 strains of CNS pertaining to 'bacteremia' and 162 strains considered as 'contaminants', with 84 (51.8%) and 52 (32.8%) positive, respectively. The slime-producing strains were significantly more resistant ( p <0.001) to cloxacillin, tobramycin, gentamicin, trimethoprim, erythromycin and ciprofloxacin.