Post-surgical nasal cellulitis outbreak due to Mycobacterium chelonae.

An outbreak of post-rhinoplasty nasal cellulitis due to Mycobacterium chelonae in a secondary care centre is described. A case-control study demonstrated that the use of inadequately sterilized surgical equipment in the Otorhinolaryngology Department was a risk factor. The causal organism was cultured from the equipment, from the surface of the operating theatre lamp, adhesive tape and from two of the hospital's general water tanks. Introduction of effective instrument sterilization methods, monitored with biological controls, the use of new air filters and cleansing and disinfection of hospital water tanks, were sufficient to control the outbreak. The antimicrobial susceptibilities of the causal organism were consistently different from those previously reported in M. chelonae.

[Usefulness of the histologic and microbiologic study of liver biopsy in the diagnosis of fever of unknown origin]. / Utilidad del estudio histológico y microbiológico de la biopsia hepática en el diagnóstico de la fiebre de origen desconocido.

Since the usefulness of liver biopsy in the diagnosis of fever of unknown origin is still controversial, we analyzed the charts of 54 patients with fever of unknown origin in whom histological and microbiological studies of a liver biopsy were performed. The cause of fever was established in 43 (80%) patients and it was most frequently of an infectious origin (52%). Histological analysis of liver biopsy was useful in determining the final diagnosis in 26 patients (48%) and was the main/only diagnostic method in a third of them. It was useful even in patients with no evidence of hepatic disfunction. Microbiological analysis of liver biopsy was positive in 7 cases (25% of infectious causes). We consider that liver biopsy should be performed early in the work-up of patients with fever of unknown origin.

Improved method for bacteriological diagnosis of spontaneous bacterial peritonitis.

The definitive diagnosis of spontaneous bacterial peritonitis is made by a positive ascitic fluid culture. Causative organisms cannot be isolated in up to 65% of patients with well-defined spontaneous bacterial peritonitis, probably due to inadequate ascites culture techniques. We prospectively compared two ascites culture methods: conventional (on chocolate agar and thioglycolate broth) and modified (inoculation of 10 ml of ascites in a tryptic soy broth blood culture bottle at the patient's bedside). In a 10-month period, 31 cirrhotic patients met our diagnostic criteria for spontaneous bacterial peritonitis; both culture methods were performed on their ascitic fluid. The conventional method grew bacteria in only 16 of the 31 episodes (52%), whereas the modified method grew bacteria in 25 (81%), a significantly higher sensitivity (P less than 0.05). The modified method also shortened significantly the time for detection of bacterial growth. We conclude that ascites inoculation into a blood culture bottle at the patient's bedside should be the routine method for ascites culture.

Epidemic of Serratia marcescens bacteremia and meningitis in a neonatal unit in Mexico City.

A case-control study was conducted on an epidemic of bacteremia and meningitis caused by Serratia marcescens in the neonatal intensive care unit and special care nursery of a general hospital in Mexico City, Mexico. A 19.9% incidence of bacteremia and meningitis was recorded in contrast to 1.4% and 3.7% during preepidemic and post-epidemic periods; a 69% mortality rate was observed. Peripheral IV catheters and the use of mixed IV fluids prepared in the wards were the major risk factors (P less than 0.001). Rectal and nasopharyngeal cultures were positive in 68% of asymptomatic neonates and hand cultures were positive in 16.7% of personnel. Strains were resistant to all aminoglycosides and broad-spectrum penicillins, and belonged to the A5/8 biogroup. Containment of this outbreak was difficult because of failure to identify colonized infants early in the epidemic and because of persistent carriage of S marcescens by personnel. Comparisons between this hospital and tertiary care centers in Mexico suggest that in developing countries nosocomial infections could be of greater magnitude in secondary than in tertiary level centers.

Control of emergence of multi-resistant gram-negative bacilli by exclusive use of amikacin.

Results of a three-year prospective study of amikacin as the only aminoglycoside used at the Instituto Nacional de la Nutrición "Salvador Zubirán" are presented. During the initial three-month baseline period, resistance to amikacin, gentamicin, and tobramycin among 870 gram-negative bacterial isolates was 3.2 percent, 17.4 percent, and 11.2 percent, respectively. In this period, the overall consumption of aminoglycosides was 69 percent for gentamicin, 30.5 percent for amikacin, and 0.5 percent for tobramycin. In the following period of exclusive amikacin use, sensitivity patterns of 9,344 gram-negative strains isolated over three years were recorded. During this period, amikacin constituted 99.3 percent of all aminoglycosides used. The percentage of gentamicin-resistant gram-negative strains declined to 7.4 percent (p less than 0.0001), whereas the percentage of amikacin-resistant strains did not change significantly. Quarterly trend analysis of aminoglycoside-resistant strains also demonstrated a significant decrease in gentamicin resistance (p less than 0.005) and an overall steady state of amikacin resistance. It is concluded that the exclusive use of amikacin was not accompanied by a significant increase in amikacin resistance during a three-year period, and may even lead to a decrease in resistance to gentamicin and tobramycin among most gram-negative organisms.

Demostracion de la permeabilidad de la valvula de Leveen por medio de la inyeccion intra-abdominal de Tc 99. / Demonstration of Leveen shunt permeability by intraperitoneal injection of Tc 99

La derivacion peritoneo yugular es un metodo propuesto por Leveen para el control de ascitis refractaria. Esta derivacion se ha popularizado y su empleo se ha difundido rapidamente. En este trabajo se describe un metodo para investigar la permeabilidad de la derivacion. El metodo consiste en la inyeccion intraperitoneal de tecnecio radioactivo que al diluirse en el liquido de ascitis puede seguirse con una gammacamara y observarse el trayecto de la derivacion y su desembocadura a nivel yugular. El metodo fue utilizado en 3 pacientes con sospecha de oclusion de la derivacion, habiendose documentado la oclusion en un caso