Gram-negative Bacilli Colonization Research Articles

High oral carriage of multidrug resistant Gram-negative bacilli in adolescents: the SOPKARD-Junior study.

The colonization of the oral cavity by potentially pathogenic antimicrobial-resistant bacteria in adolescents and its consequences is very poorly understood. The present study focused on the occurrence of oral colonization by Gram-negative bacilli (GNB) and their multidrug resistance, including the production of extended-spectrum β-lactamases (ESBLs) and carbapenemases, among healthy adolescents and risk factors associated with GNB colonization. This study was conducted as part of "A program for the early detection of risk factors for lifestyle diseases SOPKARD-Junior" (SOPKARD-Junior). Oral samples were collected from 182 adolescents from four public elementary schools in Sopot, Poland, aged 13-14 years. Bacterial strains were identified by the MALDI-TOF MS method. Screening of antimicrobial resistance was performed using a disk diffusion method. The NG-Test® CARBA-5 was used to detect and differentiate the five most widely distributed carbapenemases. Demographic and clinical data were collected and statistical analysis of risk factors was performed. A total of 68 out of 182 (37.4%) healthy adolescents was documented oral colonization with Gram-negative bacilli, including 50/182 (27.5%) multidrug resistant (MDR-GNB) strains. Over 60% of oral carriage concerned three main genera Enterobacter spp., Pseudomonas spp., and Serratia spp., which were detected in 22.1%, 19.1%, and 19.1% of participants, respectively. Citrobacter spp., Escherichia coli, Klebsiella spp., Hafnia spp., Aeromonas spp., Acinetobacter spp., and Stenotrophomonas spp. were also isolated. The antimicrobial resistance to ampicillin (100%), ceftazidime (69.1%), meropenem (60.3%), gentamycin (60.3%), piperacillin/tazobactam (52.9%), and piperacillin (45.6%) were the most common. Among 73.5% GNB strains multidrug resistance was observed, including all Pseudomonas spp. strains. Among MDR-GNB, 30.4% were resistant to four groups of antibiotics, half of the MDR Pseudomonas spp. strains were resistant to 10 groups of antibiotics. Extended-spectrum β-lactamases were produced by Enterobacter cloacae, Klebsiella spp., and Serratia spp. (7.4%). Colonization by ESBLs-positive GNB strains was significantly associated with recurrent respiratory infections, nasal congestion, and bronchitis (p<0.05). Our study revealed high oral carriage of multi-drug resistant Gram-negative bacilli in healthy adolescents and the association of ESBL-producing strains with respiratory infections. Further studies on oral colonization with GNB are necessary due to the possibility of distinct infections and the acquisition of antibiotic resistance by resident microbiota.

Carbapenem-resistant gram-negative bacterial prevention practice in nosocomial infection and molecular epidemiological characteristics in a pediatric intensive care unit

IntroductionThe increasing prevalence of carbapenem-resistant gram-negative bacilli infection has emerged as a substantial threat to human health. MethodologyIn January 2017, a screening program for carbapenem-resistant gram-negative bacilli colonization was performed in a pediatric intensive care unit (PICU). Subsequently, different strategies for carbapenem-resistant gram-negative bacilli cohorting and patient placements were introduced in January 2018. ResultsThe increase in the single room isolation (type A) and the resettlement of the same area placement (type B) resulted in a significant decrease in the nosocomial infection rate from 2.57% (50/1945) in 2017 to 0.87% (15/1720) in 2021 (P < 0.001). Notably, the incidence of nosocomial carbapenem-resistant gram-negative bacilli infections decreased in 2019 (P = 0.046) and 2020 (P = 0.041) compared with that in the respective previous year. During 2019 and 2020, a statistically significant increasing trend of type A and type B placements was observed (P < 0.05, each), which may have contributed to the decline of carbapenem-resistant gram-negative bacilli infection. The primary carbapenemase genes identified in carbapenem-resistant isolates of Klebsiella pneumoniae and Acinetobacter baumannii were blaKPC-2 from sequence type 11 and blaOXA-23 from sequence type 1712. ConclusionThe integration of various placements for patients with carbapenem-resistant gram-negative bacilli infection with active screening has been demonstrated as an effective preventive strategy in the management of carbapenem-resistant gram-negative bacilli infection.

Chlorhexidine Wipes to Reduce Multidrug-Resistant Gram-negative Bacterial Colonization and Healthcare-associated Infections among Medical Inpatients: A Cluster-Randomized Trial

Objective: To evaluate efficacy of chlorhexidine gluconate (CHG) to decolonize multidrug-resistant (MDR) gram-negative bacilli (GNB) bacteria, and to reduce healthcare associated infections (HAIs) in general medical inpatients. Materials and Methods: A 1-year, cluster-randomized study was conducted in a university hospital-based general medical unit. Eligible patients were randomized by study ward for routine daily and extra wiping with non-rinsed CHG-cloths (CHG group, n=145) or rinsed, non-medicated soap bath (control group, n=145), consecutively to the end of study. Study nurses received training and audits per CHG protocol. In all participants, axillae, groins, and perianal area were sampled to detect GNB colonization, on day 4 to 7 and day 11 to 14 of admission, by surveillance culture. All were followed for incidence rates of HAIs to day 14 of the study, or study exclusion. Results: MDR GNB colonization were significantly lower in CHG group than those of control group, both day 4 to 7 (15.9% versus 43.4%, respectively, p&lt;0.01), and day 11 to 14 of admission (20.6% versus 65.4%, respectively, p&lt;0.01). The incidence rates of overall HAIs did not differ between groups (5.80 versus 7.10 episodes per 1,000 patient-day, respectively, p=0.84). Three patients developed minor skin irritation in CHG group. Discussion: To the investigators’ knowledge, the present study is the first to demonstrate significant CHG reduction of MDR GNB colonization among medical patients in non-critical care unit. Use of non-rinsed CHG bath, personnel training, and audits, may maintain adequate skin concentration of CHG, and lower risk of cross-transmission. To effectively reduce HAIs, combined CHG bath and bundle of care may be required. Conclusion: Non-rinsed chlorhexidine baths are safe, well-tolerated, and effective to reduce MDR gram-negative bacterial colonization among general medical inpatients, and possible to lower risk of subsequent HAIs and cross-transmission, by day 14 of admission. Keywords: Multidrug-resistant gram-negative bacilli, Chlorhexidine bath, Decolonization, Healthcare associated infections, General medical inpatients

High intermittent colonization by diverse clones of β-lactam-resistant Gram-negative bacilli suggests an excessive antibiotic use and different sources of transmission in haemodialysis patients

The spread of β-lactam-resistant Gram-negative bacilli (GNB) is a topic of worldwide concern; however, knowledge about colonization by these bacteria in haemodialysis patients is limited. To analyse the dynamics and factors associated with colonization by β-lactam-resistant GNB in a dialysis centre. A longitudinal study was conducted. Stool samples were collected for each patient to evaluate extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing Gram-negative bacilli. Colonization screens were performed at three time-points and then classified as absent, intermittent, or persistent. Molecular typing included enterobacterial repetitive intergenic consensus (ERIC)-polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and multi-locus sequence typing (MLST). Clinical information was obtained from medical records and personal interview. A generalized estimating equations model was performed to determinate factors associated with the colonization. A total of 210 patients were included. ESBL-producing and carbapenem-resistant GNB colonization reached 41.2% and 11.5%, respectively. Most patients were intermittent carriers with frequencies of 73.9% and 92.95% for each bacteria group. The most frequent ESBL was CTX-M-G1, while the most common carbapenemase was KPC. ERIC-PCR and PFGE revealed high genetic diversity among strains and the Escherichia coli clone ST131 was the most important by MLST. Fluoroquinolone use (odds ratio: 3.13; 95% confidence interval: 1.03-9.44; P [cap]=0.043) and chronic obstructive lung disease (odds ratio: 3.53; 1.42-8.74; P=0.006) were associated with ESBL-producing GNB colonization. Our findings indicate a high intermittent colonization by diverse clones of β-lactam-resistant GNB in haemodialysis patients. It suggests excessive antibiotic pressure that favours the acquisition of bacteria with diverse genetic profiles and different transmission sources.

High frequency of colonization by diverse clones of beta-lactam-resistant Gram-negative bacilli in haemodialysis: different sources of transmission outside the renal unit?

Introduction. While colonization by Staphylococcus aureus in haemodialysis patients has been assessed, knowledge about colonization by beta-lactam-resistant Gram-negative bacilli is still limited.Aim. To describe clinical and molecular characteristics in haemodialysis patients colonized by S. aureus (MSSA-MRSA) and beta-lactam-resistant Gram-negative bacilli in an ambulatory renal unit.Methodology. The study included patients with central venous catheters in an outpatient haemodialysis facility in Medellín, Colombia (October 2017-October 2018). Swab specimens were collected from the nostrils and skin around vascular access to assess colonization by S. aureus (MSSA-MRSA). Stool samples were collected from each patient to evaluate beta-lactam-resistant Gram-negative bacilli colonization. Molecular typing included PFGE, multilocus sequence typing (MLST), spa typing and enterobacterial repetitive intergenic consensus-PCR (ERIC). Clinical information was obtained from medical records and personal interview.Results. A total of 210 patients were included in the study. S. aureus colonization was observed in 33.8 % (n=71) of the patients, 4.8 % (n=10) of which were colonized by methicillin-resistant S. aureus. Stool samples were collected from 165 patients and of these 41.2 % (n=68) and 11.5 % (n=19) were colonized by extended-spectrum-beta-lactamase-producing (ESBL) and carbapenem-resistant bacilli, respectively. Typing methods revealed high genetic diversity among S. aureus and ESBL-producing Gram-negative bacilli (ESBL-GNB). Antibiotic use and hospitalization in the previous 6 months were observed in more than half of the studied population.Conclusion. The high colonization by ESBL-GNB in haemodialysis patients shows evidence for the need for stronger surveillance, not only for S. aureus but also for multidrug-resistant bacilli in order to avoid their spread. Additionally, the high genetic diversity suggests other sources of transmission outside the renal unit instead of horizontal transmission between patients.

Surveillance cultures for detection of rectal and lower respiratory tract carriage of colistin-resistant Gram-negative bacilli in intensive care unit patients: comparison of direct plating and pre-enrichment step.

Purpose. Increasing consumption of colistin as treatment for infections with multidrug-resistant (MDR) Gram-negative bacilli (GNB) has been accompanied by increasingly frequent reports of colistin-resistant (ColR) MDR GNB. Higher selective pressure creates a favourable environment that can facilitate the spread of ColR isolates. Monitoring of asymptomatic ColR GNB carriage can give us a better understanding of this emerging healthcare problem, particularly in wards with higher polymyxin selective pressure and prevalence of carbapenem-resistant GNB. Our aim was to assess the ColR GNB colonization rate in intensive care unit (ICU) patients and evaluate the performance of two surveillance protocols using a selective medium.Methodology. A prospective study included 739 surveillance samples (rectal swabs and tracheal aspirates) from 330 patients that were screened for ColR GNB carriage using SuperPolymyxin medium. Two approaches were used: direct sample plating and overnight pre-enrichment of samples followed by plating. Colistin resistance was confirmed with broth microdilution. ColR isolates were molecularly screened for plasmid-mediated mcr genes.Results. A total of 44/739 samples (45 ColR GNB isolates) were positive for ColR GNB, which included 31/330 (9.4 %) colonized patients; mcr genes were not detected. The direct plating method only identified 17/45 (37.8 %) isolates correctly, whereas the pre-enrichment protocol identified all 45 ColR GNB.Conclusion. The colonization rate among our ICU patients was 9.4 %. Based on our findings, the pre-enrichment step is necessary for the determination of ColR GNB carriage - even though the time to result takes an additional day, fewer than half of ColR GNB carriers were detected using the direct plating protocol.

Reduced rate of intensive care unit acquired gram-negative bacilli after removal of sinks and introduction of \u2018water-free\u2019 patient care

BackgroundSinks in patient rooms are associated with hospital-acquired infections. The aim of this study was to evaluate the effect of removal of sinks from the Intensive Care Unit (ICU) patient rooms and the introduction of ‘water-free’ patient care on gram-negative bacilli colonization rates.MethodsWe conducted a 2-year pre/post quasi-experimental study that compared monthly gram-negative bacilli colonization rates pre- and post-intervention using segmented regression analysis of interrupted time series data. Five ICUs of a tertiary care medical center were included. Participants were all patients of 18 years and older admitted to our ICUs for at least 48 h who also received selective digestive tract decontamination during the twelve month pre-intervention or the twelve month post-intervention period. The effect of sink removal and the introduction of ‘water-free’ patient care on colonization rates with gram-negative bacilli was evaluated. The main outcome of this study was the monthly colonization rate with gram-negative bacilli (GNB). Yeast colonization rates were used as a ‘negative control’. In addition, colonization rates were calculated for first positive culture results from cultures taken ≥3, ≥5, ≥7, ≥10 and ≥14 days after ICU-admission, rate ratios (RR) were calculated and differences tested with chi-squared tests.ResultsIn the pre-intervention period, 1496 patients (9153 admission days) and in the post-intervention period 1444 patients (9044 admission days) were included. Segmented regression analysis showed that the intervention was followed by a statistically significant immediate reduction in GNB colonization in absence of a pre or post intervention trend in GNB colonization. The overall GNB colonization rate dropped from 26.3 to 21.6 GNB/1000 ICU admission days (colonization rate ratio 0.82; 95%CI 0.67–0.99; P = 0.02). The reduction in GNB colonization rate became more pronounced in patients with a longer ICU-Length of Stay (LOS): from a 1.22-fold reduction (≥2 days), to a 1.6-fold (≥5 days; P = 0.002), 2.5-fold (for ≥10 days; P < 0.001) to a 3.6-fold (≥14 days; P < 0.001) reduction.ConclusionsRemoval of sinks from patient rooms and introduction of a method of ‘water-free’ patient care is associated with a significant reduction of patient colonization with GNB, especially in patients with a longer ICU length of stay.

Molecular characterization and risk factors for carbapenem-resistant Gram-negative bacilli colonization in children: emergence of NDM-producing Acinetobacter baumannii in a newborn intensive care unit in Turkey

Multidrug-resistant Gram-negative bacilli are responsible for more than 50% of healthcare-associated infections. Colonization dynamics, characteristics, and risk factor data for CR-GNB are scarce in children. To examine the molecular characteristics of, and risk factors for nosocomial colonization with, carbapenem-resistant Gram-negative bacilli (CR-GNB) in hospitalized paediatric patients in a tertiary university hospital's paediatric units in Turkey. A prospective case-control study was performed at a university hospital in Istanbul, Turkey. A total of 1840 rectal swab specimens were collected from all 762 hospitalized children between March 2013 and October 2013. Among them, 176 (23%) patients were colonized with CR-GNB. Of these, 72 (9%) patients were colonized with carbapenem-resistant Enterobacteriaceae, 138 (18%) with CR-non-fermenter Gram-negative bacilli (CR-NF) and 34 (4%) with both. The median CR-GNB colonization time was 10 days (range: 1-116). The median duration of rectal colonization with CR-GNB was 8 days (range: 1-160). NDM (31%) was the second most frequent carbapenemase identified in Acinetobacter baumannii isolates, and has not previously been detected in Turkey. All of the 17 patients colonized with NDM-producing A. baumannii were newborns in the neonatal intensive care unit. Independent risk factors for CR-GNB colonization were: age <1 year, nasogastric tube placement, presence of underlying chronic diseases, ampicillin usage, surgical intervention, and carbapenem use. This is the first description of NDM in A. baumannii in newborn units in Turkey. Carbapenem usage is a common independent risk factor for both CRE and CR-NF colonization, which underscores the importance of antibiotic stewardship programmes.

Prevalence of multidrug-resistant organisms and risk factors for carriage in long-term care facilities: a nested case-control study

Long-term care facilities (LTCFs) are a potentially important reservoir of multidrug-resistant (MDR) organisms; however, limited data exist. A point-prevalence study was conducted in four co-located LTCFs in Australia. Nasal and rectal swabs were cultured for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and MDR Gram-negative bacilli (GNB). Molecular typing and resistance detection were performed. Risk factors for colonization with an MDR organism were determined using a nested case-control study. Consent was obtained from 115 (85%) of 136 eligible participants. Forty-one (36%) residents carried at least one type of MDR organism. The prevalence was 16% MRSA (n = 18), 6% VRE (n = 7) and 21% MDR GNB [n = 24; including extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (n = 12) and Acinetobacter baumannii (n = 6)]. The majority of ESBL-producing E. coli and A. baumannii were clonal. Current wound management [adjusted OR (AOR) 8.81 (95% CI 2.78-27.94), P < 0.001], medical device in situ [AOR 5.58 (95% CI 1.34-23.32), P = 0.018] and pressure ulcer [AOR 3.69 (95% CI 1.06-12.86), P = 0.04] were independent risk factors for MDR organism colonization. Advanced dementia [AOR 3.54 (95% CI 1.23-10.23), P = 0.02] and prolonged antibiotic use [AOR 2.95 (95% CI 1.01-8.60), P = 0.047] were independently associated with MRSA colonization, whilst current wound management [AOR 15.59 (95% CI 4.85-50.10), P < 0.001] and fluoroquinolone use [AOR 4.27 (95% CI 1.20-15.25), P = 0.025] were risk factors for MDR GNB colonization. LTCFs are an important reservoir of MDR organisms, with person-to-person transmissions being a potential issue. We have identified several predictors of colonization with MDR organisms, allowing a more targeted management of high-risk residents.

Evaluation of Potential Environmental Contamination Sources for the Presence of Multidrug-Resistant Bacteria Linked to Wound Infections in Combat Casualties

To determine whether multidrug-resistant (MDR) gram-negative organisms are present in Afghanistan or Iraq soil samples, contaminate standard deployed hospital or modular operating rooms (ORs), or aerosolize during surgical procedures. Active surveillance. US military hospitals in the United States, Afghanistan, and Iraq. Soil samples were collected from sites throughout Afghanistan and Iraq and analyzed for presence of MDR bacteria. Environmental sampling of selected newly established modular and deployed OR high-touch surfaces and equipment was performed to determine the presence of bacterial contamination. Gram-negative bacteria aerosolization during OR surgical procedures was determined by microbiological analysis of settle plate growth. Subsurface soil sample isolates recovered in Afghanistan and Iraq included various pansusceptible members of Enterobacteriaceae, Vibrio species, Pseudomonas species, Acinetobacter lwoffii, and coagulase-negative Staphylococcus (CNS). OR contamination studies in Afghanistan revealed 1 surface with a Micrococcus luteus. Newly established US-based modular ORs and the colocated fixed-facility ORs revealed no gram-negative bacterial contamination prior to the opening of the modular OR and 5 weeks later. Bacterial aerosolization during surgery in a deployed fixed hospital revealed a mean gram-negative bacteria colony count of 12.8 colony-forming units (CFU)/dm(2)/h (standard deviation [SD], 17.0) during surgeries and 6.5 CFU/dm(2)/h (SD, 7.5; [Formula: see text]) when the OR was not in use. This study demonstrates no significant gram-negative bacilli colonization of modular and fixed-facility ORs or dirt and no significant aerosolization of these bacilli during surgical procedures. These results lend additional support to the role of nosocomial transmission of MDR pathogens or the colonization of the patient themselves prior to injury.

Nasopharyngeal Gram-negative bacilli colonization in Brazilian children attending day-care centers

This study aimed at determining prevalence and resistance profile of Gram-negative bacilli isolated from nasopharynx of children attending day-care centers in Goiânia (Brazil). P. aeruginosa (100.0%), E. coli (50.0%), K. pneumoniae (35.3%), and E. aerogenes (16.7%) were the most frequent multi-drug resistant microorganisms isolated. No production of ESBL was detected.

Effect of inhaled budesonide on oropharyngeal, Gram‐negative bacilli colonization in asthma patients

The effect of inhaled budesonide on oropharyngeal Gram-negative bacilli colonization (OGNBC) in asthmatic patients was investigated. Oropharyngeal cultures were obtained from asthmatic patients attending the hospital respiratory outpatient clinic, at baseline and 1 month after treatment with 800 microg/day of inhaled budesonide. Cultures were evaluated for OGNBC and compared with those of healthy controls. A total of 148 cultures (74 from asthma patients, 74 from healthy controls) were evaluated. Six cultures (8.1%) from healthy controls, eight cultures (10.8%) from asthma patients obtained before treatment and 20 cultures (27.0%) obtained after treatment were positive for OGNBC (P < 0.05). Gender, age, presence of atopy and the degree of illness were not found to be related to the presence of OGNBC in and healthy control cultures. In the cultures obtained from the patients after treatment, OGNBC was higher in patients >50 years and in those with FEV1 < 70% (P < 0.05). Nine (18.8%) of 48 patients <50 years compare with 11 (42.3%) of the 26 patients >50 revealed OGNBC (P < 0.05). OGNBC were observed in 18.9% of the patients with FEV1 = 70% and in 47.6% of those with FEV1 < 70% (P < 0.05). The increased rate of OGNBC in asthma patients treated with inhaled budesonide was found to be related to increased age and lower level of FEV1. Further studies with larger numbers of patients are required for the interpretation of this colonization in the course of lower respiratory infections in these patients.

Prevalence and Natural History of Colonization With Fluoroquinolone-Resistant Gram-Negative Bacilli in Community-Dwelling People With Spinal Cord Dysfunction

Roghmann M-C, Wallin MT, Gorman PH, Johnson JA. Prevalence and natural history of colonization with fluoroquinolone-resistant gram-negative bacilli in community-dwelling people with spinal cord dysfunction. Objectives To estimate the prevalence of colonization with fluoroquinolone-resistant gram-negative bacilli (GNB) and to assess risk factors for and define the natural history of colonization. Design Cross-sectional study with follow-up of up to 1 year. Setting Multiple outpatient sites. Participants Eighty-four community-dwelling adults with spinal cord dysfunction. Interventions Not applicable. Main Outcome Measure Colonization of perineum with fluoroquinolone-resistant GNB. Results Overall, 24% of this community-dwelling cohort was colonized with fluoroquinolone-resistant GNB with resistance to both levofloxacin and gatifloxacin. The use of any antibiotic in the last 90 days was most strongly associated with an increased risk of colonization with fluoroquinolone-resistant GNB (relative risk, 2.3; 95% confidence interval, 1.1−4.8; P=.05). Incontinence was significantly more common among those with fluoroquinolone-resistant GNB colonization. Among the participants with incontinence (n=42), the use of intermittent catheterization (vs suprapubic, urethral, or condom catheters or overflow incontinence) was significantly protective. Colonization was not associated with an increase in urinary tract infection and was often transient. Conclusions Fluoroquinolone resistance among GNB colonizing community-dwelling people with spinal cord dysfunction is common. Colonization is more common among those receiving antibiotics and less common among those continent of urine. Among those with incontinence, those using intermittent catheterization have less colonization.

Natural history of colonization with vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, and resistant gram-negative bacilli among long-term-care facility residents.

To determine the natural history of colonization with vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and resistant gram-negative bacilli among long-term-care facility (LTCF) residents. Observational cohort study. A 355-bed LTCF with a ventilator unit and a subacute unit. Residents with colonization or infection with VRE, MRSA, or resistant gram-negative bacilli housed at the LTCF between December 1, 1999, and February 29, 2000. Cultures of clinical and surveillance sites were performed at regular intervals. Charts were reviewed for clinical characteristics associated with clearance of colonization. Kaplan-Meier curves were constructed to analyze the number of days to clearance of colonization. Forty-nine residents had 65 episodes of colonization (27 VRE, 30 MRSA, and 8 resistant gram-negative bacilli). Eighteen (28%) of the episodes cleared. The clearance rate was 2.7 episodes per 1,000 person-days. Clearance occurred significantly more often with resistant gram-negative bacilli colonization compared with VRE or MRSA colonization (6 [75%] vs 12 [21%]; P = .007; relative risk, 4.17; 95% confidence interval, 1.26 to 11.8). There was a trend toward longer use of antimicrobial agents among residents with persistent colonization. Infections occurred most frequently with MRSA. The urinary tract was the most common site of infection. Among LTCF residents, colonization with resistant gram-negative bacilli is four times more likely to clear than colonization with VRE or MRSA. Performance of surveillance cultures at regular intervals may reduce the need for contact precautions for LTCF residents with resistant gram-negative bacilli colonization.

Mechanically Ventilated Newborns: A Comparison of Two Airway Suctioning Regimens 1228

Tracheal suctioning (TS) although clinically necessary may cause hypoxemia, bradycardia, bacteremia and airway colonization. We hypothesize that some reduction of TS frequency will not adversely affect newborn care. In our NICU, TS was done q4h, but since in August 1997 the frequency was changed to q8h or as needed, a comparison of these two regimens was undertaken. TS (2 passes) was preceded by the instillation of 0.2 ml saline. Consistency, amount and color of secretions was documented. Data from 24 (q4h) and 24 (q8h) infants(bwgt. ≤1500g) on conventional ventilation for ≥7 days were analyzed. Variables studied included: reintubations (RTUB), postural drainages (PD), the incidence of bloodtinged secretions and airway colonization with Gram Positive Cocci (GPC) or Gram Negative Bacilli (GNB). Demographic and perinatal factors among the groups were similar. Infants in the q4h group (bwgt. 900g, 27w GA, 23 survivors) were comparable to those of the q8h group (bwgt. 952g, 27w GA, 23 survivors). Average number of TS/pt/d was 6 and 4.6 for q4h and q8h groups, respectively. Similar differences in TS frequency were noted at 7, 14 and 21days (p<0.01). Two pts. in the q8h group experienced nosocomial bloodstream infection (1 GPC, 1 GNB) unrelated to airway colonization. During hospitalization, newborns from both groups were RTUB on average 2.6 times, while 9 pts. (q4h) and 10 pts. (q8h) needed PD due to either atelectasis(often related to endotracheal tube malposition) or changes in quality/quantity of airway secretions. Blood-tinged secretions but not frank hemorrhage were noted during routine TS in 6 pts. (4 from q4h) and following RTUB in another 6 (5 from q8h). Eighteen pts. from each group were ventilated for at least 14 days. All but one had GPC (S.hemolyticus and/or S.epidermidis) and 22 of the 36 (q4h/q8h combined pts.) had GNB colonization. Equally distributed between the groups were:P.aeruginosa (7), H.influenzae (1), A.baumannii(2), K.pneumoniae (7), E.cloacae (1) and E.coli(4) isolates. Conclusion: A significant reduction in TS can be accomplished without affecting neonatal mortality, number of RTUB, need for PD, and timing and type of airway colonization. Significant cost benefits may be anticipated when comparable changes in the frequency of tracheal suctioning are implemented.

Neonatal airway colonization with gram-negative bacilli: association with severity of bronchopulmonary dysplasia.

Airway colonization with Gram-negative bacilli (GNB) and Gram-positive cocci (GPC) is common in mechanically ventilated neonates. Whether GNB are related to nosocomial bloodstream infection (BSI) and/or to the severity of bronchopulmonary dysplasia (BPD) is unknown. We prospectively examine this relationship using a cohort design. Data from 260 < or = 1250-g birth weight inborn infants (1991 to 1995) intubated > or = 2 weeks included 917 serial tracheal cultures and 583 blood cultures. The severity of BPD was assessed by duration of mechanical ventilation, oxygen dependency at 36 weeks of postconceptional age and the use of home oxygen supplementation. After 2 weeks of ventilation, 80% of the infants were colonized with GPC (Staphylococus epidermidis and Staphylococcus haemolyticus in 90% of the cases). Superimposed on 36% of these infants was GNB airway colonization with Klebsiella pneumoniae (25%), Enterobacter cloacae (25%), Escherichia coli (25%), Pseudomonas aeruginosa (10%), Serratia marcescen (10%), Acinetobacter baumannii and Haemophilus influenzae (5%). Comparison between 174 GPC- and 86 GNB-colonized infants showed that demographics, birth weight, gestational age, perinatal risk factors and mortality were similar. Fifteen percent of GNB-colonized infants developed BSI caused by GNB and 14% developed BSI caused by GPC. No significant temporal relationship between airway colonization and BSI was noted. GNB infants were ventilated longer and required oxygen at 36 weeks of postconceptional age and home oxygen supplementation twice as often as infants colonized only with GPC. GNB colonization was a predictor of severe BPD after controlling for ventilation. Ureaplasma colonization occurred in 28% of GNB-colonized and 33% of noncolonized infants and was not a predictor of BPD severity. GNB airway colonization creates a moderate risk for BSI. Antibiotic treatment does not regularly eradicate GNB. GNB airway colonization is associated with severe BPD, but further studies will be necessary before therapeutic efforts to eradicate GNB from the airways should be undertaken.

Selective decontamination of the digestive tract in neurosurgical intensive care unit patients

The aim of this study was to assess, in a selected population, the effects of selective decontamination of the digestive tract on colonization of the oropharynx, trachea, stomach and rectum, and on the infection rate. An economical assessment was also performed. A prospective, double-blind, randomized, placebo-controlled, dual-center trial. Two neurosurgical intensive care units. A total of 191 comatose patients admitted emergently and intubated within < 24 hrs were enrolled. Of these patients, 68 were excluded because they either died, got an early infection, or were extubated within the first 5 days. A total of 123 patients were analyzed: 63 treated and 60 placebo patients. Topical antibiotics (tobramycin, polymyxin E, amphotericin B) were applied in the oropharynx and in the stomach. Vancomycin was added in the oropharyngeal paste. Placebo patients received the same regimen (i.e., a suspension of fluid and a paste) but without antibiotics. No parenteral antibiotics were given during the study period. Bronchopneumonia episodes were diagnosed with protected specimen brush or plugged telescoping catheter and other infections were diagnosed according to the Center for Disease Control of Atlanta criteria. Antibiotic costs and cost per survivor were calculated. Selective decontamination of the digestive tract significantly reduced Gram-negative bacilli colonization as well as the number of episodes of bronchopneumonia, urinary tract infections, and sinusitis. Despite the addition of vancomycin, Staphylococcus aureus remained the main potential pathogen causing tracheal colonization and subsequent bronchopneumonia. The reduction in bronchopneumonia rate was observed in head-trauma patients only. We were able to show that: a) the trachea was the main reservoir of microorganisms responsible for pneumonia; b) pneumonia developed after tracheal colonization. Total charges for antibiotics were 2.8 times higher in the treated group than in the placebo group; in calculating the cost per survivor, selective decontamination of the digestive tract might be beneficial due to the reduced length of stay. Selective decontamination of the digestive tract is an effective technique in reducing infectious morbidity in comatose neurosurgical patients. Because of its cost, this technique should be used only in selected populations.

The Course of Nosocomial Oropharyngeal Colonization in Patients Recovering From Acute Respiratory Failure

We sought to determine the duration of nosocomially acquired Gram-negative bacilli (GNB) oropharyngeal colonization following hospitalization for acute respiratory failure (ARF). We selected 24 inpatients recovering from ARF who had positive oropharyngeal cultures for GNB. Follow-up cultures were obtained at the time of hospital discharge, and 2 and 4 weeks afterwards. The prevalence of GNB colonization in these patients was 14/21 (67 percent) at the time of hospital discharge and 14/23 (60 percent) 2 weeks afterwards. Both rates were greater than the control population's 7/30 (23 percent, p < 0.02 and < 0.05, respectively). Four weeks after hospital discharge, the prevalence of colonization had fallen to 7/19 (37 percent) which was not significantly different from that of controls. Five of 24 subjects were rehospitalized during the follow-up period. Pneumonia was diagnosed in only two of the five and both proved to be due to pathogens other than GNB. We conclude that the prevalence of GNB oropharyngeal colonization following ARF approaches control levels within four weeks of hospital discharge. We speculate that a post-ARF patient's risk for GNB pneumonia similarly declines.