Experience with infections involving the rare non-fermenter Alcaligines faecalis

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Experience with infections involving the rare non-fermenter Alcaligines faecalis

Authors:
Pooja Ajith, Saron Araya, Sridha Gona, Aaron George, Hugo Bonatti

Body of Abstract:
Background: Alcaligines faecalis is a rare non-fermentative Gram-negative rod found in water and soil and decaying material. Other previous Alcaligines spp recently underwent reclassification within the Burkholderiales order such as Achromobacter xyloxidans. Up to 25% of humans are colonized with the organism and only a limited number of infections have been published with the majority diagnosed in immunocompromised individuals.

Methods: Our institutional database was searched for all infections caused by Alcaligines faecalis during a 4-year period. Two isolates initially reported as Alcaligines xyloxidans were excluded from the study.

Results: In total 38 isolates in 33 patients were identified. Median age was 60 (range 35.3-95.6) years; 63.6% were male. Rates of comorbid conditions were DM 46%, hypertension 399%, hyperlipidemia 36%, COPD 21%, CAD 18%, and malignancies 15%. 46% of individuals were obese and 61% were active smokers. Demographic, clinical, and microbiology data are shown in table 1. Bacterial growth pattern based on streak appearance for surgical specimens was reported light in 30%, moderate in 13% and heavy in 57%; 70% of infections were polymicrobial with staphylococci in 43%, streptococci in 13%, Gram-negative rods in 28%, and anaerobes in 18% as co-pathogens. Blood cultures accounted for 6%, drainage fluids/tissue specimens for 42% and wound cultures for 42% of specimens, 9% came from drained abscesses. Only 6% of isolates came from blood cultures. Alcaligines faecalis was predominantly isolated in lower extremity soft tissue infections (88%), upper extremities were involved in 3% and another 3% were intraabdominal infections. Surgical services submitted 33% of specimens, medical services including infectious diseases 27% and the emergency department 27%; 12% of specimens came from primary care physicians. Treatment for surgical infection included incision and drainage, debridement and amputation as indicated together with antibiotics according to sensitivity testing considering the high rate of mixed infections. 

Conclusion: Alcaligines faecalis in this series was predominantly isolated in patients with chronic lower extremity infections such as diabetic foot syndrome. Whereas the majority of these infections were treated successfully, patients with Alcaligines faecalis infections had a survival of only 73% after a 2-year follow-up reflecting the high rates of comorbidities in these individuals.

Female Sex is an Independent Risk Factor for Mortality Following Post-Burn Sepsis

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Female Sex is an Independent Risk Factor for Mortality Following Post-Burn Sepsis

Authors:
Diana Julia Tedesco, Maria Fernanda Hutter, Fadi Khalaf, Marc Jeschke

Body of Abstract:
Background: Sepsis is the leading cause of morbidity and mortality among burn patients, affecting approximately 1 in 5 adults. Previous research has shown that adult female burn patients face an increased risk of mortality after injury compared to their male counterparts. However, the underlying reasons for this disparity remain unclear. It is uncertain whether the increased mortality in females is due to differences in sepsis risk, distinct physiological responses to sepsis, or variations in the timing of sepsis onset. Thus, in this study, we aim to clarify whether sex-based differences in post-burn mortality emerge primarily after sepsis develops, rather than through differential incidence of sepsis.

Methods: We conducted a cohort study at two provincial burn centres between 2006 and 2025. Patients ≥18 years with acute burn injuries covering ≥5% of total body surface area were included and stratified based on biological sex recorded on admission and sepsis diagnosis using the Sepsis-3 and ABA guidelines. Multivariable logistic regression was used to evaluate (1) the association between sex and mortality, (2) the association between sex and sepsis incidence, and (3) sex differences in 30-day mortality among patients with sepsis, adjusting for age, burn size, inhalation injury, and sepsis onset timing. 

Results: A total of 1483 burn patients were included, including 223 males diagnosed with sepsis, 844 male controls, 82 females diagnosed with sepsis, and 334 female controls. At admission, female patients were older (median (IQR) 48 (36-62) vs. 46 (22-59) years, p=0.020), had similar burn size (median (IQR) 11 (7-19) vs 12 (8-21) %, p=0.068), and similar incidence of inhalation injury (26% vs 20%, p=0.462) compared to all male patients. Overall 30-day mortality was higher in females than males (8% vs 4%, p=0.002), an association that persisted after adjustment (adjusted OR 2.20, 95% CI 1.29–3.74). Sepsis incidence (20% vs 21%, p=0.668) and the timing of sepsis onset (median (IQR) 9.5 (5-15) vs 10 (6-15) days post-injury, p=0.503) did not differ between sexes. However, among sepsis patients, females had higher 30-day mortality compared to males (20% vs 10%, p=0.031) and female sex remained independently associated with mortality after adjustment for age, burn size, inhalation injury, and sepsis onset (adjusted OR 2.97, 95% CI 1.27–6.95).

Conclusion: Female burn patients experienced higher mortality overall, and this disparity became more pronounced following sepsis. These differences were not attributable to differential sepsis incidence or timing, suggesting sex-specific biological responses to infection rather than differential exposure risk.

Hospital Trauma Volume and the Risk of Post-Injury Sepsis in Blunt Intestinal Injury: A Nationwide Analysis

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Hospital Trauma Volume and the Risk of Post-Injury Sepsis in Blunt Intestinal Injury: A Nationwide Analysis

Authors:
Yasmin Arda, Ioannis Karikis, John Hwabejire, Michael DeWane, Charudutt Paranjape, Joshua Ng-Kamstra, Lydia Maurer, Matthew Bartek, Jonathan Parks, Ali Salim, George Velmahos, Haytham Kaafarani

Body of Abstract:
Background: Blunt intestinal injury (BInI) is rare and often difficult to diagnose, resulting in delay in intervention and worse outcomes. This study aimed to evaluate whether hospital BInI volume influences the risk of post-injury sepsis in patients with BInI.

Methods: The 2017-2020 ACS-TQIP database was used to identify patients ≥18 years of age with full-thickness ileal, jejunal, or colonic perforation secondary to blunt trauma. Hospitals were stratified into tertiles by annual BInI volume. Multivariable logistic regression adjusting for demographics, comorbidities, and injury characteristics/severity was used to assess the impact of hospital volume on the risk of post-injury sepsis. To examine the potential role of delayed recognition, sensitivity analyses were conducted by stratifying patients undergoing early versus delayed (>24 hours) surgical intervention.

Results: Of 4,005,762 trauma patients, 3,954 were included: 1,397 (35.3%) in low BInI volume, 1,373 (34.7%) in medium BInI volume, and 1,184 (30%) in high BInI volume hospitals. The mean age was 41±18 years, 37% were females, the mean injury severity score was 19±10, and the most common injury was jejunal or ileal perforation (66%). On multivariable analyses, high BInI volume was independently associated with a 45% lower risk of post-injury sepsis (aOR 0.55, 95% CI 0.36-0.86) compared to low BInI volume. This association was not statistically observed in sensitivity analyses stratified by timing of surgery.

Conclusions: High trauma hospital volume of BInI is independently associated with decreased risk of post-injury sepsis. The attenuation of this effect after stratifying by operative timing may partially be related to earlier surgical intervention at high volume hospitals.

Immune cell temporal specific signatures clock track recovery status of critical injury patients

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Immune cell temporal specific signatures clock track recovery status of critical injury patients

Authors:
TeDing Chang

Body of Abstract:
BACKGROUND

Despite major advances in resuscitation and supportive care, trauma remains a leading cause of death and disability worldwide, particularly among young adults. Critical illness following severe trauma represents one of the most complex and dynamic immunological conditions encountered in modern intensive care. Survivors frequently experience prolonged recovery characterized by immune dysregulation, secondary infections, and MODS. These adverse outcomes highlight the need to understand not only the magnitude but also the temporal dynamics of immune responses during recovery from critical injury.

METHODS

We conducted a large, prospective, multicenter study enrolling 243 critically injured trauma patients and 57 healthy volunteers. Using sorted immune cell populations including T cells, monocytes, and PMNs, we constructed a comprehensive, time-resolved transcriptomic cohort of immune responses from injury onset through clinical recovery or death.

We applied three complementary analytical approaches: DEGs, WGCNA, and SLIDE to select the recovery related gene signature. From these analyses, we identified nine gene signatures associated with complicated recovery and used them to train an immune recovery clock.

We developed a novel framework, termed Temporal Gap (TempoGap), to quantify the deviation between the predicted and actual post-injury time, thereby providing a metric of immune recovery delay or acceleration. To model temporal progression, we employed the LASSO regression, optimized through 5-fold cross-validation. Model stability and performance variability were estimated via 500 bootstrapped iterations, aggregated into an ensemble of LASSO-based temporal predictors.

RESULTS

All TempoGap models showed significant associations with recovery duration. Notably, the T cell latent factor–based TempoGap demonstrated the strongest predictive effect (HR = 1.5, p < 0.001), indicating that higher expression of this temporal module was associated with faster recovery. Given the importance of early prognostication, we further evaluated model performance within the first week post-injury. The models retained substantial predictive power during this period, with the monocyte complicated recovery gene TempoGap model showing the best performance on day six (HR = 2.0, p < 0.05). Importantly, TempoGap scores exhibited only weak correlations with conventional clinical indicators, suggesting that TempoGap captures unique biological dimensions of immune recovery not reflected by traditional scoring systems. CONCLUSIONS In summary, we established an immune recovery clock model and introduced TempoGap, a novel temporal deviation metric that predicts recovery status in critically injured patients. This approach offers a conceptual and analytical foundation for precision monitoring of immune recovery, enabling early outcome prediction and guiding targeted interventions to promote recovery after critical injury.

Immunomodulatory Effect of Phospholipid Nanoparticle, VBI-S for Treatment of Sepsis.

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Immunomodulatory Effect of Phospholipid Nanoparticle, VBI-S for Treatment of Sepsis.

Authors:
Gracy Rosario, Gelilla Daniel, Benjamin Edwards, Cuthbert Simpkins

Body of Abstract:
Background: 

Sepsis, a leading cause of morbidity and mortality in humans, is an inflammatory disease caused by a dysregulated host response to an infection. Increased antibiotic resistance and lack of FDA approved drugs significantly limits treatment options for sepsis. Recently, VBI-S, a phospholipid nanoparticle colloid, has proven effective in Phase 2a clinical trial for septic shock1. Efficacy of VBI-S for septic shock is currently being evaluated in Phase III open-label randomized controlled clinical trial. 

In sepsis, macrophages play an important role in inflammation, which is one of the causes of multi-organ damage. As preliminary evidence indicates that VBI-S is effective in sepsis, we hypothesized that VBI-S is immunomodulatory in nature, and capable of reducing inflammation in septic patients. Hence, the present study initially evaluated the immunomodulatory potential of VBI-S on pro-inflammatory macrophage functions. The study analyzed the effect of VBI-S on pro-inflammatory gene expression by M1 macrophages in an in-vitro culture model. 

Methods: 

Human THP-1 monocytes were differentiated to M0 macrophages by treatment with 25nM phorbol-myristate-acetate (PMA) for 48h and then to M1 macrophages by treatment with 100 ng/ml lipopolysaccharide (LPS) and 20 ng/ml interferon gamma (IFN-γ) for 48h. Subsequently, the M1 cells were treated with different concentrations of VBI-S, (1%, 0.1%, 0.01%, 0.01%) for 24h in presence of LPS and IFN-γ for 24h. Control included M1 cells cultured in media with or without the aqueous phase. Expression of pro-inflammatory genes (CXCL10, CCR7 and IL-1b) were analyzed by quantitative SYBR Green RT-PCR. Viability of the VBI-S treated adherent M1 cells were studied by MTT assay and non-adherent floating M1 cells evaluated by Trypan blue staining. Statistical analysis was performed by Brown-Forsythe and Welsch ANOVA, nonparametric t-test and Mann Whitney U test (Graph Prism Software). 

Results: 

VBI-S significantly decreased the levels of candidate pro-inflammatory CXCL10, CCR7 and IL-1b genes in M1 cells at 1%, 0.1%, and 0.01% concentrations (P<0.05). Furthermore, the number of viable adherent or non-adherent dead cells were unaltered at 1%, 0.1%, 0.01% and 0.001% VBI-S as compared to the respective controls.  Conclusion:  VBI-S has immunomodulatory properties as it reduces pro-inflammatory cytokine/chemokine gene expression by M1 macrophages. This study points towards immunomodulation being a key mechanistic function of VBI-S in treatment of sepsis. Futuristic studies are aimed at assessing VBI-S uptake by M1 macrophages, and subsequent mechanistic actions on pro-inflammatory signaling events. 1 Simpkins C, et al., 2024: Efficacy and safety of phospholipid nanoparticles (VBI-S) in reversing intractable hypotension in patients with septic shock: a multicentre, open-label, repeated measures, phase 2a clinical pilot trial. EClinicalMedicine 68:102430.

Impact of Thoracic Irrigation on Empyema Patterns in Trauma Patients

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Impact of Thoracic Irrigation on Empyema Patterns in Trauma Patients

Authors:
Katherine Russo, Joshua Preston, Wen Yang, Randi Smith, Jonathan Nguyen, Jason Sciarretta

Body of Abstract:
Background:

Empyema is a significant complication following traumatic hemothorax, contributing to prolonged hospitalization, increased morbidity, and the need for invasive interventions. Thoracic irrigation (TI) has emerged as a minimally invasive strategy for managing retained hemothorax, yet its influence on the development and microbiologic profile of subsequent empyema remains unclear. 

Methods:

A retrospective review was performed of trauma patients who underwent TI for retained hemothorax at an urban Level I trauma center between 8/2023 and 8/2025, identifying those who subsequently developed empyema. A historical comparison cohort included all traumatic empyema cases over a four-year period (1/2019 – 7/2023) preceding TI protocol implementation. Empyema was defined by the presence of positive pleural cultures. Data collected included demographics, injury patterns, pleural microbiology, ICU length of stay (LOS), and mortality. Continuous and ordinal variables were summarized as median [IQR] and compared using the Wilcoxon rank-sum test. Categorical variables were summarized as n (%) and compared using Fisher’s exact test.

Results:

Among 124 patients who underwent TI during the study period, the overall empyema rate was 2.4%. A total of 35 culture-proven empyemas were identified: 3 post-TI patients and 32 historical controls without TI. Patients who developed empyema after TI had a significantly longer time to diagnosis compared with those without TI (30 days [29.5-33] vs. 13 days [9.8-19.5], p=0.031). Polymicrobial empyema occurred less frequently in the TI group (33% vs. 72%), though this difference did not reach statistical significance. Rates of anaerobic infection were similar between cohorts (33% vs. 41%). No significant differences were observed in demographics, injury mechanism, ISS, thoracic AIS, ICU LOS, or mortality between groups (Table 1).

Conclusion:

In trauma patients who developed empyema, those who underwent prior thoracic irrigation demonstrated delayed onset of empyema and a lower observed rate of polymicrobial infection compared with patients who did not undergo TI. Although limited by the small number of post-TI empyemas, these findings suggest that TI may influence the microbiologic profile or temporal development of pleural space infection. Larger studies are needed to clarify the impact of TI on empyema pathophysiology and clinical outcomes following traumatic hemothorax.

Improving cefazolin use for surgical antimicrobial prophylaxis in patients with penicillin allergy labels

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Improving cefazolin use for surgical antimicrobial prophylaxis in patients with penicillin allergy labels

Authors:
Sara Ausman, Jason Beckermann, Christopher Huiras, FNU Shweta, Sarah Lessard

Body of Abstract:
Background

Use of beta-lactam (BL) antibiotics for surgical antibiotic prophylaxis (SAP) has been linked to better surgical outcomes, including reduced surgical site infections and less safety events like acute kidney injury. Patients with documented reactions to penicillin or cephalosporin antibiotics often receive non-BL antibiotics which are linked to more adverse events and delays in administration.  Implementation of a new protocol supporting safety of cefazolin in patients with penicillin allergy labels (PwPALs) improves BL use in surgical and procedural prophylaxis.

 

Methods

A retrospective, pre-post analysis of SAP for PwPALs was performed in a multi-region healthcare system in Wisconsin.  Adult and pediatric PwPALs were included if antibiotics were administered as surgical prophylaxis. Patients without documented penicillin allergy labels or antibiotic doses administered were excluded. Interventions were undertaken in a step-wise approach between January 2021 and December 2023 including electronic health record allergy module enhancements, algorithm development, and point-of-care guidance to surgical clinicians. The pre-intervention (Pre-I) group reflects antibiotic doses documented in 2020 while antibiotic administrations in 2024 were included in the post-intervention (Post-I) group. A secondary analysis of PwPALs documented as anaphylaxis was also completed.

 

Results

Overall, cefazolin use improved in PwPALs from 72.9% to 91.1% between 2020 and 2024 (844/1157 doses and 1362/1495 doses, respectively).  Improvement in cefazolin prescribing was seen regardless of procedure category – clean versus clean-contaminated (Table 1).   A corresponding decrease in vancomycin prescribing for PwPALs was observed across all procedure types from 8% (74/1157) of patients receiving in 2020 compared to 0.6% (9/1495) in 2024.  Secondary analysis of PwPALs documented as anaphylaxis showed cefazolin use improved significantly from 36.2% (34/94 doses) pre-intervention to 88.2% (85/93 doses) post-intervention for all procedure types.  Similar reduction in vancomycin doses was seen in the PwPAL documented as anaphylaxis (Pre-I: 27.7%, 26/94 doses vs. Post-I 2.2%, 2/93 doses). All post-intervention changes were statistically significant (Table 1). No difference in new cefazolin allergies added to EHR or anaphylaxis surrogate markers, including administration of rescue medications or tryptase orders, were observed in the Post-I cohort. 

 

Conclusions

Use of cefazolin for surgical antimicrobial prophylaxis in patients with penicillin allergy labels, including reported anaphylaxis, is safe. Developing institutional protocols improves appropriate SAP choice in PwPALs.

Complex And Simple Appendicitis: REstrictive or Liberal postoperative Antibiotic eXposure (CASA RELAX) using Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR): a multicenter Bayesian randomized controlled trial

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Complex And Simple Appendicitis: REstrictive or Liberal postoperative Antibiotic eXposure (CASA RELAX) using Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR): a multicenter Bayesian randomized controlled trial

Authors:
D. Dante Yeh, Gabrielle Hatton, Claudia Pedroza, Rafael Torres Fajardo, Sean Thomas Dieffenbaugher, Gerd Daniel Pust, Luciana Tito Bustillos, Diedra Turnacliff, Erin Fitzgerald, Jesse Victory, Lucy Z. Kornblith, Caitlin Collins, Genna Beattie, William G. Cheadle, Nicholas Caminiti, Alonso Andrade, Susan F. McLean, Andrew Bernard, Matthew Ray, Lillian Kao

Body of Abstract:
Background: The optimal duration of antibiotics (abx) after appendectomy for simple or complicated (gangrenous or perforated) appendicitis is unknown. We performed a randomized trial to compare a restrictive to a liberal antibiotic strategy on a composite, patient-centered outcome, the Desirability of Outcome Ranking (DOOR).

Methods: Adults with appendicitis undergoing appendectomy at 9 sites were randomized 1:1 to either a Restrictive (no postop abx for simple, up to 1 day of postop abx for complicated) or Liberal (up to 1 day of postop abx for simple, 4 days of postop abx for complicated) strategy. The primary endpoint was based on DOOR, an ordinal scale of mutually exclusive clinical complications with within-category rankings determined by duration of antibiotic exposure.

Randomization was stratified by age >65 and site. Bayesian cumulative logistic models using a neutral prior were used to assess the probability of benefit with a Restrictive strategy. Posterior probabilities of benefit of Restrictive strategy were generated. Type of appendicitis (simple vs complicated) was assessed as an interaction.

Results: A total of 346 subjects (182 Restrictive, 164 Liberal) enrolled from 9 sites were included in the final analysis. Baseline demographics between groups were similar. There were 265 simple and 81 complicated (11 gangrenous) appendicitis cases. The DOOR category outcomes were similar between groups (Figure). The majority experienced the best possible outcome, DOOR 1 (Cure; no adverse effects), and no patient experienced death (DOOR 7). The Restrictive strategy had a cumulative odds ratio of 0.84 (95% CrI 0.42-1.72) for each sequential DOOR category.   This correlated with a 68% probability that Restrictive strategy reduces (improves) DOOR category. However, this finding was driven by patients with complicated appendicitis, resulting in a DOOR OR 0.69 (95% CrI 0.27-1.68), which correlates with a 79% probability that the Restrictive strategy reduces DOOR. In contrast, the Restrictive strategy with simple appendicitis resulted in a DOOR OR 1.17 (95% CrI 0.47-3.0), which correlates with a 37% probability that the Restrictive strategy reduces DOOR.

Conclusions: A Restrictive postoperative antibiotic strategy in acute appendicitis resulted in similar to mildly improved clinical outcomes, when compared to a Liberal strategy overall. The patients who benefitted most from a Restrictive strategy were patients with complicated appendicitis. Given the well-established risks of prolonged antibiotic exposure in the absence of clinical benefits, we suggest that a restrictive postoperative antibiotic strategy be adopted for patients with complicated appendicitis.

Infection Type and Class: Exploring Thrombotic and Renal Complications in a SICU Cohort

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Infection Type and Class: Exploring Thrombotic and Renal Complications in a SICU Cohort

Authors:
Ioannis Karikis, Yasmin Arda, John O. Hwabejire, Michael P. DeWane, Casey M. Luckhurst, Lydia Maurer, Joshua S. Ng-Kamstra, Haytham M. Kaafarani, George C. Velmahos, Galit H. Frydman

Body of Abstract:
Background:
 Infection-related thrombosis and organ injury are increasingly recognized in critically ill patients. Surgical ICU (SICU) patients may be particularly vulnerable because they combine severe physiological stress, complex operations, and high rates of invasive devices and broad-spectrum antimicrobials. We aimed to examine how pathogen burden and diversity relate to clinically significant adverse events in SICU patients with suspected infection. 

Methods:
 We conducted a single-center retrospective study of 137 SICU patients with suspected infection and available microbiologic data, who underwent longitudinal microbiologic sampling from 2020-2024. Organisms were grouped into four pathogen classes (Gram-positive bacteria, Gram-negative bacteria, fungi, and viruses). For each patient, we derived (1) the number of pathogen classes involved (0–4), (2) the number of distinct bacterial isolates (0, 1, 2–3, ≥4), and (3) combinations of bacteria, fungi, and viruses. The primary outcome was a major thrombotic event (deep venous thrombosis, pulmonary embolism, line thrombosis, myocardial infarction, or stroke). Secondary outcomes were AKI and hospital LOS. Associations were evaluated descriptively with univariate analysis.

Results:
 Median age was 63 (51–73) years and median hospital LOS 12 (6–25) days. Overall, 22/137 patients (16%) developed an MTE and 41/132 (31%) developed AKI. Across pathogen-class strata (N=132 with complete data), MTE rates rose from 1/44 (2.3%) with no detected class to 5/15 (33.3%) with three classes and 4/5 (80.0%) with all four classes involved (p<0.001); AKI showed a similar pattern (13.6%, 19.5%, 51.9%, 60.0%, and 80.0%, respectively; p<0.001). Median LOS increased from 12 (5.5–22.5) days with no pathogen class to 23.5 (11–30) days with three classes and 60 (50–96.5) days with all four classes (p=0.003). When stratified by bacterial isolates, MTE rose from 4/80 (5.0%) with no bacterial growth to 6/20 (30.0%) with ≥4 isolates, and AKI from 14/80 (17.5%) to 8/15 (53.3%) (both p<0.001), with LOS increasing from 8.5 (5–18) to 29 (14–54) days (p=0.002). The highest rates of MTE and AKI were observed in a small subgroup with concurrent bacteria, fungi, and viruses (57.1% and 85.7%, respectively). Conclusions:  In this SICU cohort, increasing pathogen burden and diversity were associated with higher rates of clinically significant adverse events, including major thrombotic events, AKI, and prolonged hospitalization in a graded fashion. A plausible explanation for these patterns is an underlying immunothrombotic process linking infection, thrombosis, and organ injury. These hypothesis-generating findings support larger studies to clarify causal pathways and to test strategies to prevent complications in high-risk surgical ICU patients, such as combinatorial and/or amplifying inflammatory pathways secondary to multimodal infectious stimuli.

Critical review of a series of Acinetobacter spp surgical and blood stream infections at a rural hospital in the Appalachian region

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Critical review of a series of Acinetobacter spp surgical and blood stream infections at a rural hospital in the Appalachian region

Authors:
Saron Araya, Pathya Kunthy, Sridha Gona, Aaron George, Hugo Bonatti

Body of Abstract:
Background: Acinetobacter spp are opportunistic non-fermentative Gram-negative rods, which are found in soil and water. The organisms are associated with surgical, urinary tract, respiratory tract and blood stream infections, which may be difficult to treat due to natural resistance against many antibiotics.

Methods: Our institutional database was searched for all infections caused by Acinetobacter spp during a 4-year period.

Results: In total 64 isolates in 58 patients were identified. Median age of the 38 males and 26 females was 62.6 (11.3-88.2) years. Rates of comorbid conditions were DM 33%, hypertension 38%, hyperlipidemia 31%, COPD 10%, CAD 16%, and malignancies 7%. 37% of individuals were obese and 29% active smokers. Acinetobacter baumannii was isolated in 69%, lwoffii in 17%, radioresistens 6%, ursinglis 3% and calcoaceticus, junii and species 2% each. Demographic, clinical, and microbiology data are shown in table 1. Bacterial growth pattern based on streak appearance for surgical specimens was reported light in 48%, moderate in 7% and heavy in 45%; 72% of infections were polymicrobial with staphylococci in 32%, streptococci in 13%, Gram-negative rods in 34%, anaerobes in 19% and yeast in 1% as co-pathogens. Blood cultures accounted for 34%, drainage fluids/tissue specimens for 31% and wound cultures for 33% of specimens, 12% came from drained abscesses. Lower extremity soft tissue infections were the most common manifestation with 55%, the trunk was involved in 10% and upper extremities in 2%; in 9% intraabdominal infections were diagnosed. The majority of blood cultures were sent by emergency department and 50% of the surgical specimens were submitted by podiatry. Treatment for surgical infection included incision and drainage, debridement and amputation as indicated together with antibiotics according to sensitivity testing considering the high rate of mixed infections. 

Conclusion: Acinetobacter spp infections in our rural setting were caused by a surprising variety of different strains. Clinically, one third of cases included bacteremia. The most common infection in this series was diabetic foot syndrome. The majority of these infections were treated successfully and 91% of patients were alive after a 2 year follow up.