Herman Baer

Role of hand contamination of personnel in the epidemiology of gram-negative nosocomial infections

Gram-negative organisms, responsible for a high rate of colonization and infection in an intensive care nursery, were recovered frequently from hands of personnel, despite regular hand antisepsis. In sequential hand cultures contamination of hands by gram-negative organisms was transient in some nurses, but active multiplication of the organisms occurred on the hands of others and in a few nurses a temporary carrier state appeared to exist. The results of this study suggest that the hands of hospital personnel may serve not only as a passive vehicle in the nosocomial transmission of gran-negative bacteria, but also may constitute a reservoir of nosocomial organisms.

Preautopsy magnetic resonance imaging: Initial experience

To our knowledge, there are no prospective data in the literature investigating the role of magnetic resonance imaging (MRI) in detecting abnormalities in cadavers to determine the feasibility of this concept. We prospectively studied six cadavers (three stillborn infants, one infant, and two adults) with a 0.15 T resistive magnet. The images obtained allowed detection of abnormalities in multiple organs. Although autopsy was superior to MRI in detecting very small abnormalities, MRI was equal to autopsy in detecting gross cranial, pulmonary, abdominal, and vascular pathology in this small series. In addition, MRI was superior to autopsy in detecting air and fluid in potential body spaces. Preautopsy MRI may be an alternate method in restricted or denied autopsies and may provide an additional MRI research and educational tool.

Cul-de-sac isolates from patients with endometritis-salpingitis-peritonitis and gonococcal endocervicitis.

Neisseria gonorrhoeae was cultured from the cul-de-sac in 11 of 17 patients with bacteriologically documented gonococcal endometritis-salpingitis and identified by Gram stain in one other instance. In five, N. gonorrhoeae was the only isolate. In six other patients, the presence of other aerobic (two) and anaerobic bacteria (three), as well as N. gonorrhoeae, was documented. In the remaining six patients, only aerobic and anaerobic organisms were isolated. The data are interpreted as supporting the concept of anaerobic superinfections following initial infection with N. gonorrhoeae late in the course of this disease entity.

Quantitative and qualitative effects of povidone-iodine liquid and gel on the aerobic and anaerobic flora of the female genital tract

Povidone-iodine solution (Betadine Solution) produces a dramatic fall in the numbers of total aerobes and anaerobes recoverable from the posterior vaginal pool in the first 10 minutes following administration. Within 30 to 120 minutes, near baseline counts for both aerobic and anaerobic bacteria are re-established. When the vehicle for the povidone-iodine is changed to polyethylene glycol (Betadine Vaginal Gel) an effective antibacterial effect can be documented over a 3 hour period.

Airborne contamination in orthopedic surgery. Evaluation of laminar air flow system and aspiration suit.

The question arises whether, on the basis of our studies, the laminar flow system and aspiration suit should be considered as useful and effective components of the overall proctocol to prevent postoperative surgical infections. Our observations do not permit a definitive answer. This would obviously depend on the demonstration of a reduction of the incidence of postoperative infection by means of a large controlled study. The infection rate encountered in this study can not be used to draw any conclusion as to the efficacy of the laminar flow systems, since there are too many uncontrollable variables which may be influential in causing a post operative wound infection. Published reports and present data seem to indicate that the airborne route of transmission is of little significance in modern surgery and that the amount of wound contamination is not necessarily a reflection of airborne contamination. Thus, the use of the laminar air flow system and aspiration suits, which are clearly designed to prevent wound infection by the airborne route, does not seem to be justified on this basis at the present time. On the other hand, the use of laminar air flow system and/or aspiration suit by necessity imposes a strict discipline in those operating rooms, where multiple personnel are routinely involved; i.e., they reduced the number of personnel in contact with patient, reduce the traffic about the surgical patient, etc., which may have significant benefits towards the control of surgical wound infections. This enforced discipline may very well account for the significant decrease in the number of positive intraoperative wound cultures in this study when laminar air flow systems and/or aspiration suits were in use.

Susceptibility of the Anaerobic Bacteria, Group D Streptococci, Enterobacteriaceae, and Pseudomonas to Semisynthetic Penicillins: Carbenicillin, Piperacillin, and Ticarcillin

Sodium piperacillin T-1220, a new semisynthetic penicillin, was tested in vitro against 297 clinical isolates of anaerobic bacteria and 669 aerobic bacteria by the conventional agar dilution method and compared with carbenicillin and ticarcillin. At a 100-μg/ml concentration the three drugs showed comparable effectiveness against the anaerobes tested. However, at 20 μg/ml, piperacillin was the most effective drug against Bacteroides fragilis, peptostreptococci, and group D streptococci. At this drug concentration only 48% of the B. fragilis strains exhibited susceptibility to carbenicillin only, 64% exhibited susceptibility to ticarcillin but 90% exhibited susceptibility to piperacillin. Similar findings were observed with peptostreptococci and group D streptococci. On a weight basis piperacillin was statistically shown to be the most effective antibiotic of the three tested against these anaerobes. At 20 μg/ml, piperacillin exhibited a statistically significant difference (P < 0.01) over carbenicillin and ticarcillin for Serratia marcescens, Escherichia coli, Klebsiella species, Klebsiella pneumoniae, Pseudomonas isolates, and Citrobacter diversus. At both 20- and 100-μg/ml concentrations, piperacillin appeared to be the most effective (calculated P < 0.01) upon Klebsiella species, K. pneumoniae, S. marcescens, and C. freundii in activity over ticarcillin and carbenicillin.

Clinical response of patients with gonococcal endocervicitis and endometritis-salpingitis-peritonitis to doxycycline.

The clinical response to single-drug therapy with doxycycline was evaluated in 25 patients with gonococcal endoceruicitis and was correlated with the bacterial isolates present within the cul-de-sac. The 10 patients with gonococcal salpingitis salpingitis and the three patients with gonococcal peritonitis exhibited excellent clinical responses. When polymicrobial infection coexisted with gonococcal peritonitis or functioned without the concomitant presence of Neisseria gonorrhoeae, a significantly altered therapeutic response was observed in four of the 12 patients. Four patients in this grouping exhibited either secondary temperature elevations or lack of a significant alteration of the white blood cell count, two features which were not characteristic of the patients with either gonococcal salpingitis or peritonitis. In the cases of polymicrobial peritonitis, there was a poor correlation between ensuing clinical response and in vitro resistance of one or more cul-de-sac isolated to doxycycline. The presence of a resistant organism did not preclude a good or satisfactory clinical response. The absence of a resistant organism correlated well with a good clinical response.

Treatment of uncomplicated urinary tract infections with trimethoprim versus sulfisoxazole, with special reference to antibody-coated bacteria and fecal flora.

A total of 331 college-age women with urinary tract infections were studied. These women were assigned randomly to the following groups: 50 patients treated with 400 mg of trimethoprim (TMP) per day for 14 days (designated the TMP400/14d group); 50 treated with 2.0 g of sulfisoxazole (SZ) per day for 14 days (SZ/14d group); 120 treated with 200 mg of TMP per day for 10 days (TMP200/10d group); and 111 treated with 2.0 g of SZ per day for 10 days (SZ/10d group). By the last day of therapy, clinical and bacteriological cure rates were 100% in the TMP400/14d, SZ/14d, and TMP200/10d groups and 97.1% in SZ/10d group. At 1 week after therapy ended, the initial urinary pathogens remained eradicated in 100% of the TMP400/14d group, 98.2% of the TMP200/10d group, 95.6% of the SZ/14d group, and 98.0% of the SZ/10d group at 4 weeks after therapy ended, the clinical cure rates were 92.0% in the TMP400/14d group, 92.0% in the SZ/14d group, 89.0% in the TMP200/10d group, and 90.0% in the SZ/10d group. At 4 and 24 weeks after therapy ended, the recurrence rates in the four treatment groups did not differ significantly. The antibody-coated bacteria test localized 39.5% of the infections to kidneys and 56.8% of the infections to bladders. Neither symptoms nor responses to therapy were correlated with the antibody-coated bacteria test results. Both TMP at a dose of 200 mg/day and SZ were tolerated well. TMP at a dose of 400 mg/day was associated with a skin rash in 24% of the patients receiving this therapy. TMP suppressed fecal Escherichia coli. SZ increased the number of sulfa-resistant fecal isolates; however, this phenomenon did not affect the rate of sulfa-resistant recurrences.

Comparative efficacy and safety of nalidixic acid versus trimethoprim/sulfamethoxazole in treatment of acute urinary tract infections in college-age women.

One hundred and thirty-five college-age women with acute urinary tract infections caused by gram-negative Enterobacteriaceae were treated by random allocation with either nalidixic acid (NA), 1 g every 6 h for 7 days, or trimethoprim/sulfamethoxazole (TMP/SMZ), 160/800 mg every 12 h for 10 days. The clinical and bacteriological cure rates were 98.0% in each group on the last day of therapy. At 1 and 4 week posttherapy, both the clinical and bacteriological cure rates for NA declined to 90.0 and 74.0% respectively; for TMP/SMZ, they declined to 93.0 and 72.0% respectively. By 4 weeks posttherapy, 96.0% of the TMP/SMZ group and 93.0% of the NA group had remained free of the initial urinary pathogens. Neither drug was associated with emergence of resistant bacterial mutants in urine. The antibody-coated bacteria tested (ACBT) localized 31.5% of the infections of the kidney and 67.7% to the bladder. Upper tract symptoms did not correlate with the presence of a positive ACBT. The response to therapy was similar for the two regimens regardless of ACBT results. After treatment, the emergence of resistant Enterobacteriaceae in fecal flora was 1.1% in the NA group and 2.3% in the TMP/SMZ group. The incidences of drug reactions were 7.0% with NA and 6.3% and TMP/SMZ.

Cyclic variation in the adherence of group B streptococci to human vaginal epithelial cells.

Studies conducted on three normally menstruating women demonstrated a distinct cyclic variation in adherence of group B streptococcus type III to vaginal epithelial cells. This cyclic variation consisted of a gradual rise in adherence during the first half of the menstrual cycle, reaching a maximum on day 14, followed by a sharp decline to low levels of adherence that persisted through the second half of the cycle. These changes in adherence correlated directly with the variation in the pyknotic index of the vaginal epithelial cells, suggesting that hormonal factors played a role in adherence of group B streptococci to vaginal epithelium.