Quantitative Bacterial Cultures Research Articles

Bronchoscopy Training: Current Fellows’ Experiences and Some Concerns for the Future

To determine current pulmonary fellows' perspectives about their bronchoscopy training. Survey of 59 pulmonary fellows selected by training program directors to represent their institutions. "Hands-on" symposium at the CHEST 1998 annual meeting, Toronto, Canada. Fellows reported a mean (+/- SD) of 2.4+/- 0.7 years of training, estimated they had performed 77.7+/-34 bronchoscopies per year, and had generally high estimates of their bronchoscopy proficiency and training. Proficiency estimates correlated with number of procedures cited (r = 0.43, p = 0.001) or level of fellowship training (r = 0.40, p = 0.002). Proficiency ratings (r = 0.63, p = 0.0001) and procedure numbers (r = 0.45, p-0. 0004) correlated with program quality ratings. Approaches to bronchoscopy instruction varied, and most often consisted of one-to-one instruction by faculty (92.5%), lecture-based instruction (74.6%), and case discussions (72.9%). Use of bronchoscopy lectures (p = 0.008) or videos (p = 0.057) were associated with higher self-estimates of proficiency, whereas use of lectures (p = 0.002), a bronchoscopy text (p = 0.009), and one-on-one instruction (p = 0.05) were associated with more highly ranked programs. Major components of training varied among programs. Although most fellows had received instruction encompassed in basic bronchoscopy, fewer had experience with bronchoscopic intubation (71.2%), transbronchial needle aspiration (72.9%), quantitative bacterial culture (64.4%), stent placement (27.1%), laser photocoagulation (25.4%), or cryotherapy (6.8%). Components of bronchoscopy experiences correlated with fellows' estimates of bronchoscopy proficiency and program quality. Approaches to bronchoscopy instruction and the components of bronchoscopy experiences vary considerably among institutions and are associated with pulmonary fellows' perceptions of bronchoscopy proficiency and training program quality. Definition of an optimum bronchoscopy curriculum remains necessary.

The effects of amoxicillin therapy on skin flora in infants.

In order to determine the effect of amoxicillin therapy on the perineal skin microbial flora in infants, we took quantitative bacterial and fungal cultures of perineal and sternal areas from 25 infants treated with amoxicillin (40 mg/kg/day) for 10 days. Specimens were obtained prior to therapy, within 3 days of conclusion of therapy, and 14-16 days later. Immediately following therapy, a decline in the number of bacterial isolates occurred on both the perineum (89 to 47) and sternum (84 to 39). The greatest decline occurred in the number of anaerobic bacteria (mostly Peptostreptococcus spp. and Propionibacterium acnes). Other organisms that were less often isolated were aerobic streptococci and Staphylococcus epidermidis. The number of Candida albicans isolates increased from 3 to 11 (p < 0.05) on the perineum, and 1 to 7 (p < 0.025) on the sternum. Four of the infants developed diaper dermatitis. The density of C. albicans increased more than 14-fold following amoxicillin therapy. Cultures done 14-16 days after cessation of therapy revealed an increase in the number of bacterial isolates on the perineum (47 to 72) and on the sternum (39 to 61) and a decline in recovery of C. albicans. This study demonstrates the effects of amoxicillin on the ecology of skin microbial flora in infants-a decrease in the number of bacterial isolates and an increase in recovery of C. albicans.

Effects of oral administration of metronidazole on small intestinal bacteria and nutrients of cats.

To determine effects of oral administration of metronidazole on the number and species of duodenal bacteria and selective nutrients of cats. 6 healthy domestic shorthair cats. Undiluted duodenal fluid was obtained for quantitative and qualitative bacterial culture to determine species and number of bacteria in healthy cats. Blood samples were assayed for taurine, total protein, albumin, cobalamin, and folate concentrations. Cats then were given metronidazole (20 mg/kg of body weight, PO, q 12 h) for 1 month, after which bacterial cultures and serum assays of nutrients were repeated. Nine months after cessation of antibiotic treatment, duodenal bacteria were re-evaluated and serum was assayed for total protein, albumin, cobalamin, and folate concentrations. Oral administration of metronidazole caused a significant decrease in aerobic and anaerobic bacterial counts in the duodenum of healthy cats, accompanied by emergence of Streptococcus spp and Corynebacterium spp. Serum concentrations of cobalamin and albumin increased when duodenal bacterial counts were decreased, although changes in folate or taurine concentrations were not detected. Measured variables did not differ, when comparing results obtained before and 9 months after cessation of metronidazole. Oral administration of metronidazole decreased the number of aerobic bacteria and altered indigenous flora in the small bowel of cats. Normal duodenal flora appeared to be stable, because species of bacteria were re-established by 9 months after cessation of metronidazole. Bacterial flora appeared to have an impact on nutrients, because albumin and cobalamin increased during antibiotic administration and returned to preadministration concentrations after cessation of the antimicrobial.

Correlation between endotoxin level and bacterial count in bronchoalveolar lavage fluid of ventilated patients.

To assess the predictive value of the endotoxin level in the bronchoalveolar lavage (BAL) and to propose to the clinician a guide in the diagnosis of gram-negative bacterial (GNB) pneumonia. Retrospective and prospective studies to investigate the relation between endotoxin level and quantitative bacterial culture of BAL and to test the predictive value of a defined threshold. University hospital general intensive care unit. In the first part of the study, 77 consecutive ventilated patients with clinical suspicion of nosocomial pneumonia between January 1995 and January 1996. In the second part of the study, 93 consecutive ventilated patients studied prospectively between February 1996 and April 1997. Quantitative cultures for aerobic bacteria were performed directly from the fluid. Bacterial species were determined with standard techniques. The detection of endotoxin in BAL was made using a quantitative chromogenic Limulus assay. In the retrospective analysis, a significant correlation between quantitative GNB cultures and BAL endotoxin levels was observed (r2 = 0.60, p < .0001). An endotoxin level > or = 4 endotoxin units/mL (EU/mL) distinguishes patients with a significant GNB count from colonized patients with a sensitivity of 92.6%, a specificity of 81.4% and a correct classification rate of 84.9%. In the prospective analysis, the 4 EU/mL threshold permits identification of infected patients with a sensitivity of 82.2%, a specificity of 95.6%, and a correct classification rate of 90.3%. The receiver operating characteristic curve analysis showed that the Limulus assay still had a good discrimination power in the prediction of significant bacterial count in BAL fluid. Endotoxin detection immediately after bronchoscopy is a distinct advantage to the clinician because antimicrobial gram-negative therapy may be immediately justified according to the results.

Multicenter prospective study of ventilator-associated pneumonia during acute respiratory distress syndrome. Incidence, prognosis, and risk factors. ARDS Study Group.

We investigated the incidence, risk factors for, and outcome of ventilator-associated pneumonia (VAP) in patients with acute respiratory distress syndrome (ARDS). We compared 134 patients with ARDS with 744 patients without ARDS on mechanical ventilation. Fiberoptic bronchoscopic examination and quantitative bacterial cultures (protected brush or catheter sampling [threshold: 10(3) cfu/ml], or bronchoalveolar lavage [threshold: 10(4) cfu/ml]) were used to diagnose pneumonia. VAP occurred in 49 patients (36.5%). The incidence of pneumonia was 23% (173 of 744 patients) among patients without ARDS (p < 0.002). Nonfermenting gram-negative rods caused significantly more pneumonia in ARDS patients. Mortality rates were identical in ARDS patients with (28 of 49 patients, 57%) and without (50 of 85 patients, 59%) pulmonary infection (p = 0.8). VAP resulted in a considerable increase in attributable time on mechanical ventilation of both the overall population of ARDS patients and of survivors. Both the use of sucralfate (adjusted odds ratio [OR]: 4. 42; 95% confidence interval [CI]: 2.01 to 9.7, p = 0.0002) and the duration of exposure to sucralfate (adjusted OR: 1.206; 95% CI: 1. 095 to 1.328, p = 0.0002) were associated with an increased risk of VAP during ARDS. VAP considerably prolongs the time on mechanical ventilation without affecting survival. Patients given sucralfate may be at greater risk of developing pulmonary infection during ARDS.

Quantitative Bacterial Cultures and Cytological Examination of Bronchoalveolar Lavage Specimens in Dogs

Cytology and quantitative bacterial cultures of lower respiratory tract secretions are widely used in human medicine to differentiate airway infection from simple bacterial colonization. A retrospective study was conducted to determine the usefulness of quantitative aerobic cultures and Gram stain intracellular bacteria counts from bronchoalveolar lavage (BAL) specimens in dogs in diagnosing lower respiratory tract infection (LRTI) and to determine whether chronic bronchitis is associated with marked bacterial growth in dogs. The threshold determined to define clinically relevant bacterial growth was 1.7 x 10(3) colony-forming units per milliliter of BAL fluid. We used this threshold and found that diagnostic sensitivity and specificity were 86% and 100%, respectively. With a threshold for infection of >2 intracellular bacteria observed in any of 50 fields, microscopic examination of Gram stain BAL preparations had a sensitivity of 71% and a specificity of 97% in establishing LRTI. There was a high correlation between bacterial morphology on BAL Gram stain and bacterial cultures. Combining the results of intracellular bacteria counts from the BAL Gram stain with those from the quantitative cultures, the sensitivity in diagnosing LRTI was 87% and the specificity was 97%. BAL quantitative cultures as well as quantitating intracellular bacteria on Gram stain BAL cytology were revealed to be useful in identifying LRTI in dogs. Chronic bronchitis does not appear to be associated with marked bacterial growth in dogs.

Effect of thermal injury with Pseudomonas aeruginosa infection on pulmonary and systemic bacterial clearance.

Despite improvements in burn wound care, infections, particularly pneumonia, remain a major hurdle to recovery from thermal injury. After burns, a variety of systemic immune and inflammatory changes contribute to the risk of infection. Clinically, infection coupled with burn injury seems to adversely affect susceptibility to subsequent infection. Using a mouse model of 10% total body surface area, full-thickness, third-degree burns with quantitative bacterial cultures of multiple tissues, the effect of graded intratracheal and intraperitoneal infections with Pseudomonas aeruginosa on the development of infection was assessed. P. aeruginosa infection of blood and lung were demonstrated in burned mice 4 hours after they received 1 to 7.2x10(5) P. aeruginosa intratracheally but not in unburned control mice. Disseminated infection from endogenous bacterial species (Proteus, Enterococcus, Streptococcus) involving the lungs, liver, blood, and subeschar space was observed in mice that received both burns and infection with P. aeruginosa (intraperitoneally and intratracheally) but not with infection or burn alone (p<0.01). After burns, pulmonary bacterial clearance was delayed in association with both pulmonary infection (7.2x10(5) P. aeruginosa intratracheally) and intraperitoneal infection (10(7) P. aeruginosa intraperitoneally). Histologically, diffuse pneumonitis was observed in mice that received burns and infection but not in mice with either infection or burns alone. Small thermal injuries coupled with transient infection of the lungs or peritoneum delay the clearance of bacteria from the lungs and contribute to infection of the lungs, liver, burn site, and blood by endogenous organisms. These studies support the synergy of relatively small thermal injuries with infectious exposures in the pathogenesis of pneumonia and systemic infections after burns.

Ranitidine bismuth citrate and clarithromycin, alone or in combination, for eradication of Helicobacter mustelae infection in ferrets

Abstract Objective To determine whether ranitidine bismuth citrate, clarithromycin, or a combination of ranitidine bismuth citrate and clarithromycin would be efficacious in eradication of Helicobacter mustelae infection in ferrets. Animals 60 seven-month-old ferrets. Procedure To determine dosages of clarithromycin and ranitidine bismuth citrate that would suppress growth of, but not eradicate infection with, H mustelae, ferrets (n = 6/group) were treated PO with clarithromycin or ranitidine bismuth citrate at various dosages. Efficacy of treatment was then determined by treating ferrets with clarithromycin alone, ranitidine bismuth citrate alone, or clarithromycin and ranitidine bismuth citrate. Gastric biopsy specimens were obtained before, during, and at various times after treatment and submitted for quantitative bacterial culture and histologic evaluation. Minimum concentrations of clarithromycin that inhibited 90% of the growth of isolates obtained before and after treatment were determined. Results Dosages of clarithromycin and ranitidine bismuth citrate that suppressed growth of H mustelae were 12.5 and 24 mg/kg of body weight, PO, every 8 hours, respectively. Infection was not eradicated in ferrets treated with ranitidine bismuth citrate alone but was eradicated in all 6 ferrets treated with clarithromycin and ranitidine bismuth citrate and in 4 of 6 treated with clarithromycin alone. A decrease in susceptibility to clarithromycin was detected for H mustelae isolates obtained after treatment. Mild or moderate antral gastritis was observed even in ferrets from which infection was eradicated. Conclusions and Clinical Relevance A combination of ranitidine bismuth citrate and clarithromycin was efficacious in eradicating H mustelae infection from ferrets. (Am J Vet Res 1999;60:1280–1286)

Quantitative analysis of the effect of xylitol on pneumococcal nasal colonisation in rats

Xylitol possesses anti-bacterial effects on pneumococci in vitro. To study the effect in vivo, the nostrils of 80 rats were inoculated with pneumococci. Intervention groups ( n=20) received either a xylitol diet or xylitol nasal sprays. The control groups were on a normal diet or had saline sprays. After 3 days, a quantitative bacterial culture and a PCR were done from the mucosal suspension. Neither the mean colony-forming unit counts nor the PCR counts differed statistically significant between the xylitol and control groups. Thus, we found that xylitol had no significant effect on pneumococcal mucosal colonisation.

Quantitative analysis of the effect of xylitol on pneumococcal nasal colonisation in rats.

Xylitol possesses anti-bacterial effects on pneumococci in vitro. To study the effect in vivo, the nostrils of 80 rats were inoculated with pneumococci. Intervention groups (n = 20) received either a xylitol diet or xylitol nasal sprays. The control groups were on a normal diet or had saline sprays. After 3 days, a quantitative bacterial culture and a PCR were done from the mucosal suspension. Neither the mean colony-forming unit counts nor the PCR counts differed statistically significant between the xylitol and control groups. Thus, we found that xylitol had no significant effect on pneumococcal mucosal colonisation.

Quantitation of inflammatory responses to bacteria in young cystic fibrosis and control patients.

Recent studies suggest that inflammation plays a role in the pathogenesis of lung disease in cystic fibrosis (CF). The goal of the present study was to quantitatively compare bronchoalveolar lavage fluid (BALF) inflammation and its relation to bacterial infection, between children with CF and children with other chronic respiratory problems. Differential cell counts, immunoreactive interleukin 8 (IL-8), and quantitative bacterial cultures were done in BALF from 54 CF (median age 1.8 yr) and 55 control patients (median age 1.0 yr) who underwent bronchoscopy for clinical indications. Among infected CF patients, those with Pseudomonas aeruginosa did not have more inflammation than those without P. aeruginosa. The ratio of neutrophils or of IL-8 to bacteria in BALF was significantly greater for CF patients compared with control subjects, regardless of pathogen. Calculation of linear regression for either neutrophils or IL-8, as a function of bacterial quantity, yielded positive slopes for both CF and control patients, but with significant elevations for CF. We conclude that the inflammatory response to bacterial infection is increased or prolonged in CF compared with control patients, and that this increase is not necessarily due to pathogens specific for CF (e.g., P. aeruginosa). These data may provide further rationale for anti-inflammatory therapy early in CF.

Parenteral infusions bacterial contamination in a multi-institutional survey in Mexico: Considerations for nosocomial mortality

Background: Parenteral infusions can be contaminated during administration (extrinsic contamination). A previous survey found that extrinsic con-tamination was not uncommon in a hospital in Mexico with lapses in aseptic techniques. To determine whether this problem exists in other similar institutions, we undertook a multi-institutional study. Methods: We surveyed 6 hospitals (A to F) lacking an infection control committee to determine the level of extrinsic contamination. We visited each hospital and obtained samples of all the parenteral infusions in use, drawing 0.5–1 mL from the tubing injection port. Quantitative and qualitative bacterial cultures were performed. Chlorine levels of the tap water were measured. Visits were repeated until the survey was completed. Results: A total of 751 infusions were cultured, of which 16 (2.13%) were contaminated. Hospital contamination rates varied from zero to 5.56%. Klebsiella pneumoniae was the most common isolate (10 cases). During the first sampling day in hospital C, the 7 infusions from the pediatric ward were found to be contaminated with a similar K pneumoniae strain. In-service education was started in this hospital. Infusion contamination was eliminated followed by a reduction in mortality rate. Overall, a higher risk for infusion contamination was noted for pediatric patients (P =.01, odds ratio = 3.28, 95% CI, 1.10–9.91) and in wards with inadequate water chlorine levels (P =.02, odds ratio = 3.64, 95% CI, 1.08–13.51). Conclusions: If the hospitals surveyed are representative of others in developing countries, an endemic level of parenteral infusion contamination could exist in many hospitals throughout the world. (AJIC Am J Infect Control 1999;27:285-90)

The diagnostic value of gram stain of bronchoalveolar lavage samples in patients with suspected ventilator-associated pneumonia.

Ventilator-associated pneumonia (VAP) is one of the most common causes of morbidity and mortality in intensive care unit patients. However, the diagnosis is quite difficult. Gram stain (GS) of bronchoalveolar lavage (BAL) sample is a time-saving diagnostic method for VAP. However, its clinical significance has not been adequately investigated. The aim of this study was to determine its sensitivity and specificity for VAP diagnosis. We prospectively performed GS and quantitative bacterial cultures (QBC) of BAL samples, obtained through fiberoptic bronchoscope, in 75 consecutive postoperative and/or multiple trauma patients with suspected VAP. We considered BAL-GS as positive for VAP diagnosis when (i) polymorphonuclear neutrophils were > 25 per optic field at a magnification x 100 (p.o.f x 100); (ii) squamous epithelial cells were < 1% p.o.f x 100; and (iii) one or more microorganisms were seen p.o.f. at a magnification x 1,000 (p.o.f. x 1,000). VAP was diagnosed with criteria similar to those used in previous studies. Pneumonia was the final diagnosis in 22/75 (29%) patients. The BAL-GS was positive in 17/22 patients with VAP and in 7/53 patients without VAP. Accordingly, the sensitivity of BAL-GS for VAP diagnosis was 77%, the specificity 87%, the positive predictive value 71% and the negative predictive value 90%. Our data suggest that BAL-GS has good sensitivity and high specificity for VAP diagnosis. It could therefore constitute a useful complementary tool in the task of early diagnosis and treatment of VAP.

Elemental content of airway surface liquid from infants with cystic fibrosis.

We tested the hypothesis that airway surface liquid (ASL) electrolyte composition is altered in infants with cystic fibrosis (CF) and that the presence of airway inflammation affects ASL composition. We measured the tracheal ASL sodium and chloride concentration and examined bronchoalveolar lavage (BAL) fluid cytology, interleukin-8 (IL-8) concentrations, and quantitative bacterial culture in 19 infants and young children with CF. Seven infants undergoing bronchoscopy for the evaluation of stridor served as non-CF controls. In addition, we measured nasal ASL sodium and chloride concentrations from 10 young adults with CF and from 10 control subjects. On the basis of the BAL findings, the infants with CF were divided into three groups: one with little evidence of pulmonary inflammation (CF-NI, n = 5); one with obvious pulmonary inflammation (CF-I, n = 7); and an intermediate group (CF-MI, n = 7). We found the ASL sodium was not different among any of the four groups (means mM +/- SE, 85 +/- 10 controls; 78 +/- 16 CF-NI; 83 +/- 9 CF-MI, 84 +/- 9 CF-I). In contrast the ASL chloride was lower in the CF-NI group when compared with control subjects (108 +/- 5 control subjects; 77 +/- 7 CF-NI, p < 0.01). In the CF-I and CF-MI groups, the ASL chloride concentrations were of intermediate values (CF-I 95 +/- 10 mM; CF-MI 96 +/- 9 mM) and not significantly different from controls. Results from the nasal ASL analysis showed no significant differences in sodium and chloride concentrations in the CF group compared with control subjects. These results suggest that the primary abnormality of ASL composition is a reduction in chloride concentration. ASL composition appears to be affected by the presence of airway inflammation.

Bronchoscopic Evaluation of Pulmonary Infiltrates Following Bone Marrow Transplantation

To determine the impact of fiberoptic bronchoscopy (FOB), including quantitative bacterial cultures obtained by BAL and protected specimen brushing on therapeutic decisions and outcome in bone marrow transplant (BMT) patients. Retrospective review of all BMT patients undergoing FOB during a 4-year period. A tertiary care university hospital. Three hundred five patients underwent BMT; 71 (23%) had FOB to assess pulmonary infiltrates. Allogeneic BMT recipients underwent FOB 3.37 times more often than autologous recipients (p < 0.001). Pathogens were identified in 31 (46%) patients undergoing FOB; bacteria were most commonly isolated although 86% of patients had received broad-spectrum empiric antibiotics. Therapy was changed in 20 (65%) patients when a microorganism was identified and in 9 (22%) with nondiagnostic results (p = 0.0026), but isolation of a presumed pathogen had no apparent effect on survival. There were 19 (27%) FOB complications, including bleeding in 8 (11%) patients and death in 2 (3%). Major complications were associated with prolonged prothrombin time (p = 0.006) and were more common (36% vs 14%; p < 0.05) in patients who had protected specimen brushing vs BAL alone. Mortality at 40 months in BMT patients not requiring FOB was 33% compared with 61% mortality in those undergoing FOB (p < 0.001); mortality was 96% in patients with respiratory failure requiring mechanical ventilation. FOB is diagnostically useful in the evaluation of some BMT patients with pulmonary complications and often influences therapy, although no impact on survival was clearly demonstrated. FOB should be performed only after benefits of the procedure are weighed carefully against its increased risk in this select population.

Adverse metabolic and microbiological effects of tube feeding in experimental canine obstructive jaundice.

Inadequate oral intake and poor absorption result in malnutrition in obstructive jaundice. Both malnutrition and obstructive jaundice promote bacterial translocation from the gut. This study was designed to test the efficacy of tube feeding in preventing malnutrition and in decreasing the metabolic and microbiological adverse effects in obstructive jaundice. Forty adult mongrel dogs were studied and were allocated into one of four groups: group I (PO-control) underwent sham ligation of the common bile duct (CBDL) and was fed ad libitum on Portagen (Mead Johnson, Evansville, IN); group II (PO-CBDL) underwent CBDL and was ad libitum fed on the same formula; group III (FEG-control) underwent sham CBDL and received forced esophagogastric feeding (FEG) with Portagen; and group IV (FEG-CBDL) underwent CBDL and received FEG. All the animals underwent insertion of a F-12 feeding tube to the stomach from an esophagotomy wound on day 1 and the tube was used for continuous enteral feeding with Portagen over 4 h/d from day 2 until day 13 in groups III and IV. Fourteen days later, blood samplings were done and a laparotomy was performed to obtain liver, mesenteric lymph nodes (MLN), and terminal ileum for quantitative bacterial culture. Bacterial translocation to MLN and liver was represented by log10 CFU/g of tissue in this study. Both group II and IV animals with CBDL significantly lost body weight (p = .0001) and had a lower level of prealbumin (p = .0054). A significant increase in bacterial translocation to MLN and to liver occurred in groups II and IV (p = .0017 and .0268, respectively). Intestinal bacterial population was also higher in these two groups than in the other two controls (p = 0.0028). An increase in plasma ammonia level was found in dogs with CBDL (p = .0002) and in dogs with FEG (p = .003), compared with their respective controls. Three among 13 dogs in group IV died and no mortality occurred in the other groups (p = .223). Tube feeding fails to improve malnutrition in obstructive jaundice and is associated with intestinal bacterial overgrowth, promoting bacterial translocation to MLN and liver, precipitating liver dysfunction and consequently a higher mortality.

Bacteriologic diagnosis of respiratory tract infection

The use of the Gram stain for determination of the presence of bacteria in respiratory secretions is described. Success of the procedure depends on the use of fresh samples of high cellular quality. The Gram stain can be used to distinguish the presence (among other organisms) of Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catarrhalis enterobacteria and Pseudomonas. This paper also discusses the use of sputum samples for bacteriologic culture and the value of bacterial counts in expectorated sputum, and describes the use of transtracheal aspiration and transthoracic aspiration puncture. Finally, it considers the optimum procedures for the testing of antibiotic susceptibility of presumptive pathogens isolated from the lower respiratory tract.

Prospective Evaluation of a Semiquantitative Dip Slide Method Compared With Quantitative Bacterial Cultures of BAL Fluid

Quantitative bacteriologic workup of BAL fluid (BALF) has evolved as a sensitive and specific technique for the diagnosis of bacterial pneumonia. Conventional quantitative cultures are expensive, time-consuming, and often unavailable on a 24-h basis. Therefore, we evaluated a dip slide method for the semiquantitative measurement of bacterial cultures in BALF specimens and compared the results with those from conventional quantitative cultures. Fifty BALF specimens from 45 patients with suspected pulmonary infection were examined prospectively with both methods. We compared the microbiologic results of conventional quantitative cultures with those of the dip slide method that is commercially available for blood cultures. Cost-effectiveness analysis of both methods was performed. In 37 BALF specimens, 64 bacterial strains were detected with both techniques. The dip slide method and conventional cultures showed a high correlation with respect to the colony counts of the individual organisms per milliliter BALF (r=0.935; p= 0.0001) and the sum of colony counts in individual patients (r=0.947; p=0.0001). Although five strains were not detected by the dip slide technique, the diagnostic accuracy was not influenced. In 13 BALF samples, there was no growth of bacteria with both techniques. While the diagnostic yield of both methods was similar, the dip slide technique was 44 to 66% less expensive than conventional cultures. The examination of BALF with a clip slide method is highly comparable to conventional quantitative culture techniques, less expensive, and can be used independently of a specialized microbiology laboratory on a 24-h basis.

Topical ointment therapy benefits premature infants

Premature infants have an ineffective epidermal barrier. The aim of this study was to investigate the cutaneous and systemic effects of preservative-free topical ointment therapy in premature infants. We conducted a prospective, randomized study of 60 infants less than 33 weeks' estimated gestational age. The treated infants received therapy for 2 weeks with twice-daily preservative-free topical ointment therapy while the control group received no topical treatment or as-needed therapy with a water-in-oil emollient. Data collection included transepidermal water loss (TEWL) measurement, skin condition evaluations, fungal and quantitative bacterial skin cultures, analysis of fluid requirements, patterns of weight low or gain, and the incidence of blood and cerebrospinal fluid cultures positive for microorganisms. We found that topical ointment therapy significantly decreased TEWL during the first 6 hours after the initial application. TEWL was decreased by 67% (p = 0.0001) when measured 30 minutes after application and 34% (p = 0.001) when measured 4 to 6 hours after application. We also observed significantly superior skin condition scores in the treated group on study days 7 and 14 (p = 0.001) and 0.0004, respectively). Quantitative bacterial cultures revealed significantly less colonization of the axilla on day 2, 3, or 4 and on day 14 (p = 0.008 and 0.04, respectively). The incidence of positive findings in blood and/or cerebrospinal fluid cultures was 3.3% in the treated group of infants versus 26.7% in the control group (p = 0.02). There was no statistical difference in the fluid requirements or patterns of weight gain or loss during the 2 weeks of the study. Preservative-free topical ointment therapy decreased TEWL for 6 hours after application, decreased the severity of dermatitis, and decreased bacterial colonization of axillary skin. Infants treated with ointment had fewer blood and cerebrospinal fluid cultures positive for microorganisms. These data support the use of topical ointment therapy in very premature infants during the first weeks after birth.

Bronchoalveolar lavage or oropharyngeal cultures to identify lower respiratory pathogens in infants with cystic fibrosis.

As collections of lower respiratory tract specimens from young children with cystic fibrosis (CF) are difficult, we determined whether oropharyngeal cultures predicted lower airway pathogens. During 1992-1994, 75 of 90 (83%) infants with CF diagnosed by neonatal screening had 150 simultaneous bronchoalveolar lavage (BAL) and oropharyngeal specimens collected for quantitative bacterial culture at a mean age of 17 months (range, 1-52). Ten children undergoing bronchoscopy for stridor served as controls. Total and differential cell counts and interleukin-8 concentrations were measured in BAL fluid. A subset of bacterial pathogens were typed by pulsed field gel electrophoresis. A non-linear relationship with inflammatory markers supported a diagnosis of lower airway infection when > or = 10(5) colony-forming units/ml were detected. This criterion was met in 47 (31%) BAL cultures from 37 (49%) children. Staphylococcus aureus (19%), Pseudomonas aeruginosa (11%), and Hemophilus influenzae (8%) were the major lower airway pathogens. In oropharyngeal cultures, S. aureus (47%), Escherichia coli (23%), H. influenzae (15%), and P. aeruginosa (13%) predominated. The sensitivity, specificity, and positive and negative predictive values of oropharyngeal cultures for pathogens causing lower respiratory infections were 82%, 83%, 41%, and 97%, respectively. When there was agreement between paired oropharyngeal and BAL cultures, genetic fingerprinting showed some strains of the same organism were unrelated. We conclude that oropharyngeal cultures do not reliably predict the presence of bacterial pathogens in the lower airways of young CF children.