Achromobacter Xylosoxidans Bloodstream Infection in Elderly Patient with Hepatocellular Carcinoma: Case Report and Review of Literature

Sepsis Due to Achromobacter xylosoxidans in a Tertiary Care Centre: Case Series

Achromobacter xylosoxidans, also known as Alcaligenes xylosoxidans, is a low-virulence, non-fermenter gram-negative bacillus mainly found in marine environments. We report a detailed series of four high-risk cases of septicemia with the common variable of positive blood cultures for A. xylosoxidans. All four blood isolates were multi-drug resistant and susceptible to meropenem and trimethoprim-sulfamethoxazole. Two patients responded well to the treatment with meropenem and trimethoprim-sulfamethoxazole and two patients died. It should never be assumed that Achromobacter is a contaminant even though it is relatively infrequently isolated from clinical samples. This infection can progress to fatal bacteremia, even in otherwise healthy people, and it can potentially cause severe conditions in premature infants. With only a limited number of antibiotics demonstrating bactericidal properties, the possibility of failure in empirical treatment is significant. As a result, it is important to have a precise comprehension of this uncommon yet deadly illness in order to increase the probability of successful treatment.

An 18-Year Dataset on the Clinical Incidence and MICs to Antibiotics of Achromobacter spp. (Labeled Biochemically or by MAL-DI-TOF MS as A. xylosoxidans), Largely in Patient Groups Other than Those with CF

Achromobacter spp. are intrinsically multidrug-resistant environmental microorganisms which are known to cause opportunistic, nosocomial, and sometimes chronic infections. The existing literature yields scarcely any larger datasets, especially with regard to the incidence in patient groups other than those with cystic fibrosis. The aim of this study was to fill this gap. We present a retrospective analysis of 314 clinical and 130 screening isolates detected in our diagnostic unit between 2004 and 2021, combined with patients’ demographic and clinical information (ward type and length of hospitalization), and the results of routine diagnostic antibiotic MIC determination. We found the apparent increase in prevalence in our diagnostic unit, in which cystic fibrosis patients are an underrepresented group, in large part to be attributable to an overall increase in the number of samples and, more importantly, changes in the diagnostic setting, such as the introduction of rigorous screening for Gram-negative multidrug-resistant pathogens. We found these Achromobacter spp. to be most commonly detected in urine, stool, wounds and airway samples, and found the resistance rates to vary strongly between different sample types. Intestinal carriage is frequently not investigated, and its frequency is likely underestimated. Isolates resistant to meropenem can hardly be treated.

Treatment of Achromobacter Ventilator-Associated Pneumonia in Critically Ill Trauma Patients

BACKGROUND

Achromobacter sp are nonfermenting Gram-negative bacilli (NFGNB) that rarely cause severe infections, including ventilator-associated pneumonia (VAP). Data on the treatment of Achromobacter pneumonia are very limited, and the organism has been associated with a high mortality rate. Thus, more data are needed on treating this organism.

OBJECTIVE

To evaluate the treatment of Achromobacter VAP in critically ill trauma patients.

METHODS

This retrospective, observational study evaluated critically ill trauma patients who developed Achromobacter VAP. A previously published pathway for the diagnosis and management of VAP was used according to routine patient care. This included the use of quantitative bronchoscopic bronchoalveolar lavage cultures to definitively diagnose VAP.

RESULTS

A total of 37 episodes of Achromobacter VAP occurred in 34 trauma intensive care unit patients over a 15-year period. The most commonly used definitive antibiotics were imipenem/cilastatin, cefepime, or trimethoprim/sulfamethoxazole. The primary outcome of clinical success was achieved in 32 of 37 episodes (87%). This is similar to previous studies of other NFGNB VAP (eg, Pseudomonas, Acinetobacter) from the study center. Microbiological success was seen in 21 of 28 episodes (75%), and VAP-related mortality was 9% (3 of 34 patients).

CONCLUSIONS

Achromobacter is a rare but potentially serious cause of VAP in critically ill patients. In this study, there was an acceptable success rate compared with other causes of NFGNB VAP in this patient population.

Native-valve endocarditis caused by Achromobacter xylosoxidans: a case report and review of literature

Achromobacter xylosoxidans is a Gram-negative aerobic bacterium first described by Yabuuchi and Ohyama in 1971. A. xylosoxidans is frequently found in aquatic environments. Abdominal, urinary tract, ocular, pneumonia, meningitis, and osteomyelitis are the most common infections. Infective endocarditis is rare. As far as we know, until now, only 19 cases have been described, including this current report. We report the case of community-acquired native valve endocarditis caused by A. xylosoxidans in an elderly patient without a concomitant diagnosis of a malignancy or any known immunodeficiency. The patient presented with a 2-month history of fever, weight loss, and progressive dyspnea. On physical examination, mitral and aortic murmurs were present, along with Janeway's lesions, and a positive blood culture for A. xylosoxidans. The transesophageal echocardiogram showed vegetation in the aortic valve, which was consistent with the diagnosis of infective endocarditis.

Bacterial and viral contamination of breathing circuits after extended use - an aspect of patient safety?

BACKGROUND

In the past, anaesthetic breathing circuits were identified as a source of pathogen transmission. It is still debated, whether breathing circuits combined with breathing system filters can be safely used for more than 1 day. The aim of this study was to evaluate the transmission risk of bacteria and also viruses via breathing circuits after extended use.

METHODS

The inner and outer surface of 102 breathing circuits used for 1 day and of 101 circuits used for 7 days were examined for bacteria and viruses. Additionally, 10 and 20 breathing circuits each were examined after use on patients with pulmonary virus infection and with multidrug-resistant organism (MDRO) colonisation/infection respectively. Bacteria were detected by standard microbiological procedures; PCR techniques were applied for herpes simplex virus, cytomegalovirus, influenza, parainfluenza and respiratory syncytial virus.

RESULTS

Endoluminal bacterial contamination of breathing circuits remained unchanged after 7-day vs. 1-day use (5.9% vs. 7.8%) [CI95%: -0.0886-0.0506, pnon-inferiority 0.0260]. Only outside surface contamination with bacteria belonging to environmental species or human flora increased (16.8 vs. 6.9%) [CI 95%: 0.0118 - 0.1876, pnon-inferiority 0.8660]. Viruses occurred on the patient side, but not in breathing circuits. No MDRO occurred in the 20 circuits after use on patients harbouring such germs.

CONCLUSION

Endoluminal contamination of breathing circuits with bacteria did not increase after extended use. No viruses were detected in the breathing circuits using filters. Based on our results, the extended use of ABC without exceptions appears safe, if a high level of anaesthesia workplace cleaning is secured.