Handwashing and disinfection of heavily contaminated hands—effective or ineffective?

Hands are among the principal vehicles for transfer of nosocomial pathogens in hospitals. Often, outbreaks of infection are thought to be caused by a lack of compliance with handwashing guidelines, rather than due to the inadequacy of the handwashing agents used. In this study the effectiveness of proper handwashing and the use of three different hand disinfectants: ethanol 70% (E), isopropanol 40% (I) and alcoholic chlorhexidine (70%) (AC) was compared using three volunteers whose fingertips were heavily contaminated with a succession of bacteria including: Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Enterobacter cloacae. After each contamination, thorough handwashing and application of one disinfectant on the hands were performed three times. Fingerprint-samples were taken before and 1 min after application of the disinfectants. Thorough handwashing with an ordinary liquid soap ('Sterisol') did not reduce the confluent growth of bacteria on fingertips for any of the species used (197 examinations). Only AC had a significant effect on fingers heavily contaminated with S. aureus (126 examinations; AC compared with E and I; P less than 0.0002 and P less than 0.0002 respectively), but did not completely eradicate the bacteria. After contamination with Ent. cloacae (118 examinations), none of the three agents were particularly effective, but E and AC seemed to be somewhat more effective than I (P less than 0.0002 and P less than 0.01 respectively). When successive contamination was performed using all bacterial species, AC was the most effective decontaminant. However, Ent. cloacae was still present on the fingertips after 15 repeated courses of handwashing and applications of disinfectants. Bathing of hands in AC for 20s completely eradicated all bacteria from the hands. The study demonstrates that, when heavily contaminated, an ordinary handwashing followed by disinfectants is not enough to eradicate potentially pathogenic bacteria from the hands.

[Hospital infections. Extended hospital queues and unnecessary costs of the health services]

In Norway the prevalence of nosocomial infections is 5-20%; more than 50,000 patients per year. The consequences may be serious for the individual patient and his family, a serious problem for the hospital department concerned and a burden on the Norwegian health services. Nosocomial infections can be treated by antimicrobial drugs which generate selective pressure towards more resistant organisms. Infections caused by resistant strains may result in longer hospitalization, more difficult treatment, and more severe illness. In future, efforts must be directed at preventing nosocomial infections by means of education, surveillance and control.

Ciprofloxacin versus a tobramycin/cefuroxime combination in the treatment of serious systemic infections: a prospective, randomized and controlled study of efficacy and safety

Sequential intravenous and oral ciprofloxacin (CF) was compared with a combination of tobramycin and cefuroxime (T/C) in the treatment of serious systemic infections. Altogether 310 patients were randomized, 160 receiving CF and 150 T/C, the 2 groups being reasonably well balanced. 29 patients without infection were excluded from the analysis. Complete clinical resolution was obtained in 75% (107/143) patients receiving CF and in 78% (107/138) receiving T/C; the difference was not statistically significant. The rate of bacterial eradication in septicaemia was 72% (95% confidence interval (95% c.i.): 58-86%) for patients treated with CF and 87% (95% c.i.: 77-96%) when T/C was given, while the eradication rates in urinary tract infection were 72% (95% c.i.: 54-90%) and 45% (95% c.i.: 23-67%) for CF and T/C, respectively. Significant differences in bacteriological response for other diagnoses were not detected. Also for lower respiratory tract infections (LTRI) the clinical and bacteriological responses were quite similar, although relatively more failures occurred in CF treated patients with LRTI caused by pneumococci. The frequencies of adverse reactions were comparable, but the reactions were less serious following CF treatment. Our results indicate that CF may be used for empirical treatment of serious infections. However, if pneumococcal etiology is likely, alternative antibiotics should be used, and if necessary, coverage against anaerobic bacteria should be added.

[Urinary tract infections. Views on microbiological diagnosis and resistance determination]

Urinary tract infection is a common problem affecting every fifth woman during her life. Although the clinical diagnosis is easy, and is based mainly on symptoms and microscopy of urine sediment, the microbiological diagnosis is often difficult. Escherichia coli is the main etiologic agent, causing urinary tract infection in approximately 80% of the cases. Adherent, uropathogenic E coli strains are associated with pyelonephritis and relapse. Staphylococcus saprophyticus is a frequent cause of urinary tract infections in fertile women. The urethral syndrome, caused by several agents, is an important factor in differential diagnosis. Microscopy is the cornerstone of all diagnostics of urinary tract infections. A urine culture that is taken, handled, transported and interpreted satisfactorily can provide valuable information with respect to diagnosis, treatment, prophylaxis and epidemiology.

[Bacterial resistance against beta-lactam antibiotics]

Beta-lactam antibiotics include the penicillins, cephalosporins, oxacephems (moxalactam), carbapenems (imipenem) and monobactams (azthreonam)--all with a common beta-lactam ring. Beta-lactam antibiotics block the synthesis and growth of the bacterial cell wall by binding to penicillin-binding proteins on the cytoplasma membrane. The bacteria may escape the effect of beta-lactam antibiotics by reducing the permeability of the cell wall (gramnegative bacteria), by producing beta-lactamases, by reducing the affinity for beta-lactams in their penicillin-binding proteins, or by developing tolerance to beta-lactam antibiotics. A combination of these resistance mechanisms may be found in the most resistant bacteria, such as Pseudomonas, Serratia and Enterobacter; bacteria often involved in nosocomial infections. Increased antibiotic pressure may select for beta-lactam resistance among other bacteria as well, such as staphylococci, streptococci, Haemophilus influenzae, meningococci and gonococci. Prudent use of antibiotics is mandatory essential to ensure a bactericidal effect of this most important and valuable group of antibiotics in the future.

[Bacterial adhesion. An important pathogenetic factor]

Bacterial adherence is usually the first step of an infection. Bacteria bind to receptors on cell surfaces by different adhesins like fimbriae, fibrillae or lipoteichoic acid. The reseptors may be glucolipids, with sugar molecules like galactose (Gal-Gal), and present on the mucosa of the urinary tractus. Other receptors are glucoproteins or fibronectin. Important non-specific receptors are foreign material or implants in the body. Symptoms of infection generally occur from bacteria that are a) only adherent, b) adherent and toxin producing, or c) adherent and then invasive. Urogenital, gastrointestinal or respiratory tract infections are often caused by adherent bacteria. Adherent bacteria may also play an important role in infections of newborns. Invasive bacteria seem to be able to switch off their adhesins, or cover them by capsulae or human proteins, when such is necessary in order to escape human defendence mechanisms.

[Enterobacter cloacae infections at the Regional Hospital in Tromsø]

Enterobacter cloacae was isolated from 69 patients hospitalized at the University Hospital of Tromsø, Norway, during a period of 18 months. The total lethality was 11.6% (8/69) and death occurred most often in patients with a serious underlying condition. Death due to septicaemia occurred in 4/10 patients. Multiple beta-lactam resistant strains were present in 15 patients and were associated with septicaemiae (7/10, p less than 0.0005). Cephalosporin treatment had been given to every third patient (24/69), and nearly half of them (10/24) were infected by multiple beta-lactam resistant E cloacae. E cloacae occurred mainly as a nosocomial infection, since more than 70% of all patients infected had been treated by an invasive procedure prior to isolation of the bacterium. A high number of E cloacae strains were from operation wounds, especially among patients at the Department of Surgery (22/30). At this Department, the total number of E cloacae, and especially the number of multiresistant strains, was markedly reduced during restricted use of cefalosporins.

Septicaemia caused by an Enterobacter cloacae strain varying in resistance against cephalosporins

Enterobacter cloacae, sensitive to third-generation cephalosporins (cefotaxime and ceftazidime), was isolated from the stoma of a patient with leukaemia. One month later, he developed a fatal septicaemia, caused by an identical strain isolated from blood cultures. He had been treated with several antibacterial agents, including cefotaxime. The blood culture strain seemed to be a mixture of four variants with different resistance patterns to cefotaxime and ceftazidime. One variant was extremely sensitive to third-generation cephalosporins, one was completely resistant, and two showed variations in zone diameter within sensitivity group 2, both for cefotaxime and ceftazidime. Minimal inhibitory concentration (MIC) studies also showed different resistance patterns between the four variants. Similar variants were found when the stoma isolate was further investigated.

Endotoxin liberation studied by biological and chemical methods. Chemical characterization of six meningococcal lipopolysaccharides

Release of endotoxin (or lipopolysaccharides, LPS) from four meningococcal strains was studied with a chemical and a biological technique. Two strains were endotoxin-liberating (E+; 270E+ and 840E+) and two had no or low endotoxin release E-; 270E- and 840E-). LPS was quantitated by gas chromatography (GC) of LPS-specific hydroxy fatty acid, in parallel with assay of endotoxin by Limulus Amebocyte Lysate (LAL), in cell suspensions of equal O.D. and in filtered samples. The GC and LAL methods showed a reasonably good agreement in the determination of LPS in filtrates, which had distinctly higher levels (approx. 10-100 times) for the E+ strains than the E- strains, in accordance with earlier LAL studies. This difference was not due to overproduction of LPS in the E+ strains, since all four strains had the same level of LPS (by GC) in cell suspensions of equal O.D. Here the agreement between the GC and LAL methods was substantially less, with lower values by LAL for the two E-strains. The chemical composition of purified LPS was determined by methanolysis and GC for the four strains and for two additional strains 247 and 714 with a high degree of genetic similarity with strains 270E- and 840E-, respectively. Amounts of unphosphorylated L-glycero-D-mannoheptose and 2-keto-3-deoxyoctonic acid were the same in all 6 LPS. Otherwise distinct differences were found between LPS of the 6 strains. LPS of the two E+ strains formed one group with about 2.4 mol of galactose (gal), 1.4 mol of glucose (glc) and 2.8 mol of glucosamine (glcN) in the carbohydrate chain. Another group, LPS of all the E- strains except 270E-, had 1.1 mol of gal, 2.8 mol of glc and 1.3 mol of glcN in the LPS chain. LPS 270E- also had 1.3 mol of glcN but deviated strongly form all other LPS by a complete lack of gal and glc. On the basis of genetic evidence strain 270E- is regarded as a "rough" LPS mutant of strain 247. The atypical chemistry of LPS 270E- may explain an observed hydrophobicity of this LPS, and it may be related to the previously described sulfonamide sensitivity. Whether the chemical difference observed for LPS of the E+ and E- strains is a mere coincidence remains to be elucidated by detailed studies of more strains of known tendency of endotoxin liberation.

Endotoxin release from neisseria meningitidis. Relationship between key bacterial characteristics and meningococcal disease

A method was established in order to measure total and filtrable (CF) endotoxin in cultures of Neisseria meningitidis strains. The Limulus lysate (LAL) test gave results which paralleled those of the standard rabbit pyrogen test and of gas chromatography (GLC), concerning detection of different CF endotoxin levels. Meningococci varied in their ability to produce CF endotoxin. Cultures of similar bacterial densities, whether with a high (E+) or a low (E-) release of endotoxin in CF, had both high yields of endotoxin in sonicated culture suspensions determined by the LAL test. GLC demonstrated only small differences in total LPS contents between E+ and E- strains. This suggests that strains with similar cell wall endotoxin contents may vary in CF endotoxin. Electron microscopy revealed that E+ strains presented a high number of free, outer cell wall fragments (blebs, tubuli, membranes and aggregates of such structures) in surroundings. Few such free, small structures were found around E- strains. The amount of CF endotoxin of E+ strains was in part a function of the number of colony forming units (CFU/ml), and generally followed the growth curve. Because of its moment of appearance, and also based on electron microscopy findings, CF endotoxin appeared mainly to be released from living bacteria. The CF level of endotoxin was low or not detected at all in cultures of E- strains although their cultures reached higher mean CFU-levels than the niveaus required for the detection of CF endotoxin in the E+ strains. The E+ property was strain dependent. Meningococci isolated from CSF or blood had a significantly higher proportion of E+ strains (88.2%) and a higher CF endotoxin titre (greater than or equal to 10(3); 34.5%), than isolates from carriers (32.3% and 10.8%, respectively) (p less than 0.001 and p less than 0.001, respectively). A high mean CFU/ml in cultures seemed to be more often associated with isolates from patients than from carriers, more often with the presence than abscence of capsular polysaccharide (p less than 0.05), and more often with the presence than absence of the E+ property (p = 0.002). E+ strains were mostly serogroupable (i.e. encapsulated), regardless of source of the isolate (99% case and 80% carrier isolates). In contrast, serogroupable bacteria were not necessarily E+ when isolated from carriers (54.8%). The serogroup most apt to cause disease tended to have the highest proportion of E+ strains and the highest level of CF endotoxin.(ABSTRACT TRUNCATED AT 400 WORDS)

[Nosocomial infections with resistant Enterobacter cloacae. Effects on the disease and the treatment]

We describe five patients with serious nosocomial infection caused by resistant Enterobacter cloacae. Four of the patients underwent cardiovascular operations and were infected with an identical, multiple beta-lactam resistant E cloacae strain. The fifth patient was admitted with several wounds and skin-ulcers containing both resistant and sensitive E cloacae of other types. The resistant strain caused septicemia in four patients; three developed multiorgan failure and one died. The most probable causes of these infections were an abundant and constant reservoir of E cloacae in a sink at the operating unit, periodical breakdown of barriere routines, and heavy use of cephalosporins.

[Isolation of Staphylococcus in Northern Norway. Identification and effects of antibacterial agents]

53 Staphylococcus aureus and 100 Staphylococcus epidermidis consecutive routine isolates were collected from hospitalized (H) and non-hospitalized (NH) patients in Northern Norway. A coagulase slide test for rapid identification of the cell-bound coagulase of S. aureus was just as sensitive as slower tests such as the tube test for free coagulase, anaerobic acid production from mannitol, and the DNase test. Close to 80% of S. aureus isolates showed beta-lactamase production. There was no difference in sensitivity between S. aureus strains isolated from H patients and NH patients respectively. All strains were sensitive to erythromycin, oxacillin, cephalothin, tetracyclin, trimethoprim, gentamicin, clindamycin, vancomycin, and rifampicin. Most isolates showed strong sensitivity to other cephalosporins than cephalothin (although less sensitive to 3. generation cephalosporins), fucidic acid and chloramphenicol. Thus, with exception of the first generation penicillins, in our region S. aureus is still strongly sensitive to most antimicrobial agents used both in hospital and in ambulatory practice. Approximately 50% of the 68 S. epidermidis isolates from urine showed beta-lactamase activity, as against almost 80% of other clinical specimens. Urine isolates were fairly often trimethoprim resistant (29.4%) and had a slightly higher resistance than S. aureus had to several antimicrobial agents. There was no difference in the resistance pattern among urinary isolates from H patients and from NH patients respectively. S. epidermidis isolates from 32 other clinical specimens from H patients showed a substantially higher pattern of resistance compared with urine isolates. Resistance against gentamicin was found in 40.6%, and against oxacillin in 9.4%. Gentamicin resistant strains were also resistant to several other broad spectrum agents. All strains were highly sensitive to vancomycin and clindamycin.

Multiply beta-lactam resistant Enterobacter cloacae infections linked to the environmental flora in a unit for cardiothoracic and vascular surgery

During the period March 1987-May 1988, postoperative infection or colonization with Enterobacter cloacae occurred in 9/379 (2.4%) patients who underwent cardiovascular surgery. Five of the patients were infected with multiply beta-lactam resistant E. cloacae, of whom 4 had been infected with an identical, resistant strain during intervals of months. This strain was also found in the environmental flora of the cardiovascular operating suite and in a sink reservoir in the surgery department. All 4 patients with the identical resistant strain had serious complications during the postoperative period with symptoms of septicaemia in 3, multiorgan failure and shock in 2, and mediastinitis in 3. The single resistant strain of a different serotype was also associated with severe postoperative complications. The 4 sensitive strains were all different serotypes. None caused septicaemia, one was associated with mediastinitis, another with an uncomplicated sternum infection, and 2 were from sputum. In the 3 latter patients with sensitive strains and few postoperative complications, cephalosporins had not been used during the pre- or postoperative period.

Multilocus genotypes of two strains of Neisseria meningitidis and their presumed variants obtained upon subcultivation

Loss of sulfonamide resistance and endotoxin liberation have been described in two strains of Neisseria meningitidis serogroup B, upon subcultivation every 1 to 2 months over an 18-month period. Subsequently, the two laboratory variants, designated 270E- and 840E-, were also found to differ from the parent strains, 270E+ and 840E+, in serotype, outer membrane protein pattern, and virulence in mice. We report here the multilocus genotypes determined by enzyme electrophoresis, of the four isolates 270E+, 270E-, 840E+, and 840E-, and demonstrate that 270E- and 840E- strains could not have originated from subcultivation of 270E+ and 840E+, respectively, but that a mix-up of strains has occurred.

Septic abortion caused by Salmonella enteritidis

Septic abortion caused by salmonella infection is rare. Here we report a case of septic abortion due to Salmonella enteritidis. The route of infection was probably transplacental.

Endotoxin liberation associated with growth, encapsulation and virulence of Neisseria meningitidis

Endotoxin liberation, encapsulation and growth was studied in 123 isolates of Neisseria meningitidis. Free endotoxin appeared in culture filtrates during exponential growth. Meningococci with free endotoxin titre greater than or equal to 10(2) (E+) showed a higher mean number of viable bacterial counts (CFU/ml) during growth than isolates with titre less than 10(2) (E-), p less than 0.001. Differences in endotoxin liberation was, however, far more pronounced than what was indicated by growth differences alone. E+ property and increased growth rate was significantly more often found among encapsulated than non-encapsulated meningococci. Within the serogroup B isolates, there tended to be a higher mean number of CFU/ml during growth in E+ than E- meningococci, particularly among carrier isolates studied separately (p = 0.009). Case isolates of B meningococci, which had generally a higher amount of capsular material and a higher proportion of E+ strains, had also higher mean CFU/ml than B carrier isolates. This indicates that the endotoxin liberation and growth may be correlated to presence and amount of capsular polysaccharide. Endotoxin liberation, presence of capsular polysaccharide and growth ability are 3 factors which are likely to coincide in meningococci. This combination of properties may be of importance for the development of meningococcal disease.

Endotoxin liberation from Neisseria meningitidis isolated from carriers and clinical cases

Endotoxin liberation was studied in a blinded material of 121 Neisseria meningitidis isolates; from nasopharynx of 58 carriers and from cerebrospinal fluid or blood of 63 cases with meningococcal disease. Endotoxin activity in culture filtrates was determined by a Limulus lysate test. Meningococci isolated from clinical cases were significantly more frequently endotoxin-liberating (E+) (84.1%) than in carriers (25.9%); p less than 0.001. Serogroupable carrier isolates had a significantly higher frequency of E+ meningococci (61.9%) than non-groupable ones (5.4%); p less than 0.002. Serogroup B case isolates, which generally had a larger amount of capsular polysaccharide than B meningococci from carriers, had a significantly higher proportion of E+ meningococci than group B from carriers; p = 0.007. All 7 serogroup C isolates were E+ (5 cases and 2 carriers). No correlation was found between endotoxin liberation and the serotype: subtype 15:P1.16, tested by a selection of monoclonal antibodies, or between endotoxin liberation and sulfonamide resistance, when carrier and case isolates were studied separately. Meningococci isolated from cases had the following mean endotoxin titres: 320.5 in the meningitis group, 408.2 in the septicaemic group, 462.1 in the septicaemic and meningitis group, and 123.7 in the group with other systemic disease. E+ meningococci were isolated from 5/6 fatal cases. Thus, endotoxin liberation from meningococci is strongly, but not completely associated with establishment of meningococcal disease and with the presence of capsular polysaccharide.

Endotoxin release from invasive meningococci related to sulfonamide resistance, serogroup and serotype

The relationship between endotoxin liberation, sulfonamide resistance, serogroups and serotypes was studied in 28 Neisseria meningitidis strains isolated from patients with meningococcal disease. Sulfonamide resistance was present in 15/28 strains. 22 strains belonged to serogroup B, and 5 to group C; 1 strain was non-groupable. Free endotoxin activity in growing cultures of meningococci with endotoxin titre of greater than or equal to 10(2) was found in 27/28 strains. A high endotoxin activity was present in both sulfonamide-sensitive and -resistant invasive meningococci. A high endotoxin release with titre greater than or equal to 10(3) seemed to be more associated with serogroup C than B, and more to the serotypes 2 and 15/16 than to the non-typable strains.

Benzylpenicillin in mice. Effect of meningococci on plasma concentrations

Plasma concentration studies were performed in mice given high intravenous (i.v.) bolus injections or subcutaneous (s.c.) depot doses of benzylpenicillin. There was a marked difference in plasma concentration within and between individuals both after benzylpenicillin (BP) given i.v. and after benzylpenicillin procaine (BPP) given s.c. BP given i.v. resulted in a plasma half-life of 15.2 minutes, while BPP given s.c. resulted in a plasma half-life of 2.7 hours. Infection with an endotoxin-liberating meningococcal strain in BP-treated animals increased the plasma levels of BP compared with uninfected controls.

The virulence in mice of Neisseria meningitidis variants differing in free endotoxin activities and cell envelope properties

The virulence of two serogroup B meningococcal strains (270E+ and 840E+) having a high endotoxin release during in vitro growth, was compared with the virulence of corresponding variants (270E- and 840E-) liberating less endotoxin. The E-variants were isolated during subcultivations from the E+ strains. 270E+ and 840E+ were both serotype 15:P1.16, while 270E- was serotype 15:P1.2 and 840E- was non-typable. The SDS-PAGE patterns of the E+ and E- variants were also dissimilar. The E+ and E- variants differed in several other properties. Groups of mice were inoculated intravenously (i.v.) or intraperitoneally (i.p.) with E+ and E- meningococci. The endotoxin activities of inoculates and mouse blood were assayed by a Limulus lysate test. The mice received a similar infective dose of E+ and E- variants. A higher level of CFU and endotoxin was found in heart blood of E+ than of E-infected mice during the first hours after infection. Both 30h and 72h after inoculation, E+ variants were significantly more lethal to mice than E- variants (p less than 0.01).

Effect of benzylpenicillin in mice infected with endotoxin-liberating or non-liberating variant strains of Neisseria meningitidis

The effect of benzylpenicillin treatment was studied in mice infected intraperitoneally (i.p.) with endotoxin-liberating (E+) and non-liberating (E-) meningococci derived from the same original serogroup B strain. The E+ meningococci were significantly more virulent to mice than the E- variants in untreated animals (p less than 0.001). Large doses of benzylpenicillin given intravenously (i.v.) immediately after i.p. inoculation of E+ or E- meningococci resulted in complete, or almost complete survival. When treatment started later the number of surviving E- infected animals increased in all treatment regimens. By contrast, E+ infected animals had one or more treatment groups in all regimens that did not respond to benzylpenicillin at all. Benzylpenicillin treatment was given over a period of time as intermittent, regular i.v. doses, or as a depot preparation subcutaneously (s.c.). The mortality observed in E+ infected mice after benzylpenicillin i.v. was 75%, after benzylpenicillin procaine s.c. 82.5%, while animals receiving only saline i.v. had a mortality of 67.5%. The corresponding mortalities for E- infected animals were 15% (p = 0.0014), 42.5%, and 42.5%, respectively.

Endotoxin liberation and invasivity of Neisseria meningitidis

The relationship between endotoxin liberation and invasiveness was studied in 50 strains of Neisseria meningitidis isolated from blood or cerebrospinal fluid (CSF) of 16 patients with invasive disease, from nasopharynx of 9 patients with upper respiratory tract symptoms, and from nasopharynx and rectum (1, serogroup W-135) in 25 persons examined for venereal disease. Meningococci varied in their ability to liberate endotoxin. Free endotoxin was partly a function of growth and seemed to be associated with certain properties of the individual strain. Strains isolated for patients with invasive disease liberated significantly more endotoxin than strains isolated from the venereal group (p less than 0.002). All 16 invasive strains were sulfonamide resistant, against 5/9 strains from patients with upper respiratory disease symptoms and only 4/25 strains from the venereal group. The difference between the invasive group and the venereal group was significant (p less than 0.002). Serogroup A, B, C meningococci liberated significantly more endotoxin than non-A, B, C strains (p = 0.01, and serogroup A, B, C strains isolated from nasopharynx tended to have a higher endotoxin release than non-A, B, C strains isolated from the same place (not significant). Serogroup B meningococci were most frequently isolated both from patients with invasive disease and from the nasopharynx of the persons examined for venereal disease. Serogroup B meningococci had significantly more free endotoxin when isolated from blood or CSF than when isolated from nasopharynx of presumably healthy persons (p = 0.002).

Sulfonamide resistance in Neisseria meningitidis strains liberating various amounts of free endotoxin

The relationship between sulfonamide susceptibility and the ability to liberate endotoxin was studied in 50 strains of Neisseria meningitidis. The endotoxin activity was investigated by the Limulus lysate test in growing cultures of 25 sulfonamide-resistant and 25 sensitive strains. The sulfonamide-resistant strains tended to have a higher endotoxin activity in cultures grown for 6 h than sensitive ones, and had also a higher amount of free, filtrable endotoxin.