Skin and soft tissue infection caused by Achromobacter xylosoxidans: report of 14 cases

A case of community-acquired spondylodiscitis caused by Achromobacter xylosoxidans

Achromobacter xylosoxidans is a Gram-negative, aerobic, non-fermenting bacillus mainly responsible for nosocomial infections. We report the first case of community-acquired spondylodiscitis caused by Achromobacter xylosoxidans in a 61-year-old woman, immunocompromised with necrotizing dermohypodermitis of the right lower limb successfully treated with ertapenem and ciprofloxacin.

Achromobacter pneumonia in a patient with advanced COPD, a diagnostic challenge

Bacterial pneumonia causes significant morbidity and mortality especially in elderly and immunocompromised hosts. Achromobacter xylosoxidans denitrificans pneumonia is very rarely reported. However, the reported cases have been in patients who are either immunocompromised or have bronchiectasis. We hereby present a unique case of Achromobacter xylosoxidans denitrificans pneumonia in an immunocompetent patient with advanced chronic obstructive pulmonary disease (COPD). Our patient is a Caucasian male admitted with shortness of breath, fever and cough. Chest X-ray demonstrated right-sided infiltrates and he was treated with intravenous ceftriaxone and azithromycin. He was discharged home on oral amoxicillin-clavulanate 875-125 mg two times per day for a total of 7 days. Patient returned to emergency room after 5 weeks with persistent symptoms and chest X-ray revealed persistent right-sided infiltrate and sputum culture showed Achromobacter xylosoxidans denitrificans. The patient was started on oral levofloxacin 750 mg one time per day for 2 weeks with resolution of symptoms.

Polymyxin Resistance and Heteroresistance Are Common in Clinical Isolates of Achromobacter Species and Correlate with Modifications of the Lipid A Moiety of Lipopolysaccharide

The Achromobacter genus includes opportunistic pathogens that can cause chronic infections in immunocompromised patients, especially in people with cystic fibrosis (CF). Treatment of Achromobacter infections is complicated by antimicrobial resistance. In this study, a collection of Achromobacter clinical isolates, from CF and non-CF sources, was investigated for polymyxin B (PmB) resistance. Additionally, the effect of PmB challenge in a subset of isolates was examined and the presence of PmB-resistant subpopulations within the isolates was described. Further, chemical and mass spectrometry analyses of the lipid A of Achromobacter clinical isolates enabled the determination of the most common structures and showed that PmB challenge was associated with lipid A modifications that included the addition of glucosamine and palmitoylation and the concomitant loss of the free phosphate at the C-1 position. This study demonstrates that lipid A modifications associated with PmB resistance are prevalent in Achromobacter and that subresistant populations displaying the addition of positively charged residues and additional acyl chains to lipid A can be selected for and isolated from PmB-sensitive Achromobacter clinical isolates. IMPORTANCE Achromobacter species can cause chronic and potentially severe infections in immunocompromised patients, especially in those with cystic fibrosis. Bacteria cannot be eradicated due to Achromobacter's intrinsic multidrug resistance. We report that intrinsic resistance to polymyxin B (PmB), a last-resort antimicrobial peptide used to treat infections by multiresistant bacteria, is prevalent in Achromobacter clinical isolates; many isolates also display increased resistance upon PmB challenge. Analysis of the lipopolysaccharide lipid A moiety of several Achromobacter species reveals a penta-acylated lipid A, which in the PmB-resistant isolates was modified by the incorporation of glucosamine residues, an additional acyl chain, loss of phosphates, and hydroxylation of acyl chains, all of which can enhance PmB resistance in other bacteria. We conclude that PmB resistance, particularly in Achromobacter isolates from chronic respiratory infections, is a common phenomenon, and that Achromobacter lipid A displays modifications that may confer increased resistance to polymyxins and potentially other antimicrobial peptides.

Opportunistic Pathogens in Cystic Fibrosis: Epidemiology and Pathogenesis of Lung Infection

Cystic fibrosis (CF) is one of the most common life-shortening genetic diseases in Caucasians. Due to abnormal accumulation of mucus, respiratory failure caused by chronic infections is the leading cause of mortality in this patient population. The microbiology of these respiratory infections includes a distinct set of opportunistic pathogens, including Pseudomonas aeruginosa, Burkholderia spp., Achromobacter spp., Stenotrophomonas maltophilia, anaerobes, nontuberculous mycobacteria, and fungi. In recent years, culture-independent methods have shown the polymicrobial nature of lung infections, and the dynamics of microbial communities. The unique environment of the CF airway predisposes to infections caused by opportunistic pathogens. In this review, we will highlight how the epidemiology and role in disease of these pathogens in CF differ from that in individuals with other medical conditions. Infectious diseases (ID) physicians should be aware of these differences and the specific characteristics of infections associated with CF.

Ethnobotanical and antibacterial study of Primula plants traditionally used in the indigenous communities of Western Himalaya, Pakistan

Background

The upper belt of Azad Kashmir is a hilly, mountainous, and remote area where the indigenous communities mainly believe in traditional medicines for the treatment of different ailments. This study aimed to conserve scientifically and culturally important medicinal knowledge of Primula species in Azad Kashmir, Western Himalaya, Pakistan. The additional objective was to evaluate the antibacterial activity of these plants against pathogenic bacteria.

Methods

The ethnomedicinal data of Primula species was explored by conducting structured interviews with 40 informants of the study area, especially asking about the medicinal uses of Primula species. The indigenously used Primula species were further analyzed for their antibacterial activity against both gram-positive and gram-negative bacteria by using disc diffusion assay supplemented with a more robust minimum inhibitory concentration assay.

Results

Ethnomedicinal data revealed that indigenous communities living in upper regions of Azad Kashmir use 5 Primula species for the treatment of various disorders. The highly cited disease category was ophthalmic disorders. P. denticulata and P. macrophylla were the most cited plant species with higher use reports such as 104 and 93, respectively. One or more extracts of different parts of Primula species showed a noteworthy antibacterial activity against one or more tested bacteria.

Conclusion

This study provides novel information regarding several categories of traditional uses and antibacterial activity of Primula species in Azad Kashmir, Western Himalaya. The need for novel and more effective drugs derived from natural products is more important than ever, making future studies on herbal remedies both justified and urgently required.

Achromobacter spp. Surgical Site Infections: A Systematic Review of Case Reports and Case Series

Achromobacter species are isolated from rare but severe healthcare-associated infections, including surgical site infections. They are considered to preferentially infect immunocompromised patients but so far with limited evidence. We conducted a systematic review on Achromobacter spp. surgical site infections (SSIs) to determine if such infections were indeed more commonly associated with immunocompromised patients. The secondary objective was to describe the characteristics of infected patients. Eligible articles had to be published before 30 September 2020 and to report Achromobacter spp. SSIs across all surgical specialties excluding ophthalmology. Analyses were performed on individual data without meta-analysis. Cases were divided into 2 subgroups: one group which had either prosthesis or implant and the other group which did not. A first selection led to a review of 94 articles, of which 37 were analyzed. All were case reports or case series and corresponded to 49 infected patients. Most of the patients were under 65 years of age and had undergone a heart or digestive surgery followed by deep infection with no co-infecting pathogens. Nine out of the 49 cases were immunocompromised, with similar distribution between the two subgroups (16.6% and 20%, respectively). This review suggests that Achromobacter spp. SSIs do not preferentially target immunocompromised patients.

Meropenem-Resistant Achromobacter xylosoxidans, Subspecies Denitrificans Bacteremia in a Patient With Stage IV Adenocarcinoma of the Lung

Achromobacter xylosoxidans,subspecies denitrificans is a rare Gram-negative bacillus that causes health care associated infections in immunocompromised hosts. Carbapenems and anti-pseudomonal penicillins are listed as suitable empiric therapy in the literature. Herein, we report a case of a 77-year-old male with stage IV adenocarcinoma of the lung who presented with and was improving from Salmonella javiana enterocolitis, only to subsequently develop A. xylosoxidans,subspecies denitrificans bacteremia that was resistant to both meropenem and piperacillin-tazobactam. With empiric antibiotic coverage falling short of microbial clearance, timelyin vitrosusceptibility testing and prompt infectious disease consultation are of the utmost importance for treatment.

Severe cellulitis caused by Achromobacter xylosoxidans after allogeneic hematopoietic stem cell transplantation

Achromobacter xylosoxidans (A. xylosoxidans) is an aerobic gram-negative bacillus and often isolated from aquatic environments. It is supposed to cause infections in patients with malignancy or immunodeficiency. It causes various healthcare-associated infections, but cellulitis is rare. Herein, we report the first case of sever cellulitis by A. xylosoxidans after allogeneic hematopoietic stem cell transplantation (HSCT). A 49-year-old man underwent allogeneic HSCT from 8/8 HLA-matched unrelated donor with myeloablative conditioning for relapsed acute myeloid leukemia. He developed skin chronic graft versus host disease 11 months after HSCT. During the prolonged treatment with prednisolone and cyclosporine, he developed cellulitis on his left leg and admitted to our hospital. Blood and exudate culture revealed A. xylosoxidans. Although empirical therapy with cefepime was ineffective, his symptoms were dramatically improved after administration of meropenem. To our knowledge, this is the first case of A. xylosoxidans cellulitis after allogeneic HSCT. A. xylosoxidans should be considered as a possible cause of cellulitis in post-allogeneic HSCT patients on prolonged immunosuppressive therapy.

Achromobacter Infections and Treatment Options

Achromobacter is a genus of nonfermenting Gram-negative bacteria under order Burkholderiales Although primarily isolated from respiratory tract of people with cystic fibrosis, Achromobacter spp. can cause a broad range of infections in hosts with other underlying conditions. Their rare occurrence and ever-changing taxonomy hinder defining their clinical features, risk factors for acquisition and adverse outcomes, and optimal treatment. Achromobacter spp. are intrinsically resistant to several antibiotics (e.g., most cephalosporins, aztreonam, and aminoglycosides), and are increasingly acquiring resistance to carbapenems. Carbapenem resistance is mainly caused by multidrug efflux pumps and metallo-β-lactamases, which are not expected to be overcome by new β-lactamase inhibitors. Among the other new antibiotics, cefiderocol, and eravacycline were used as salvage therapy for a limited number of patients with Achromobacter infections. In this article, we aim to give an overview of the antimicrobial resistance in Achromobacter species, highlighting the possible place of new antibiotics in their treatment.

The effect of essential oils and their combinations on bacteria from the surface of fresh vegetables

During the study, we determined the antimicrobial activity of different selected essential oils (thyme, lemongrass, juniper, oregano, sage, fennel, rosemary, mint, rosehips, dill) on some pathogenic and spoilage bacteria isolated from the surface of various fresh vegetables. At the same time, in the case of some volatile oil combinations we followed the phenomena of synergism and antagonism. The identification of the isolated bacterial strains was made using 16S rDNA gene sequence analysis. The most resistant isolates appeared to be Curtobacterium herbarum, Achromobacter xylosoxidans, and Enterobacter ludwigii, while Pseudomonas hibiscicola was the most sensitive. Of the chosen plant essential oils, the most pronounced antimicrobial effect was detected in the case of oregano. The essential oils of thyme and mint also showed elevated antimicrobial activity. A synergistic effect was observed in case of five combinations of essential oil. Based on the results, we find that some individual essential oils and mixture compositions (due to synergic effect) could be good candidates for the preservation of fresh vegetables. These preliminary findings suggest that essential oils from locally grown spices could contribute to decreasing the health risk and also to the suppression of emergence of antibiotic resistance.

High Levels of Oxidative Stress Create a Microenvironment That Significantly Decreases the Diversity of the Microbiota in Diabetic Chronic Wounds and Promotes Biofilm Formation

Diabetics chronic wounds are characterized by high levels of oxidative stress (OS) and are often colonized by biofilm-forming bacteria that severely compromise healing and can result in amputation. However, little is known about the role of skin microbiota in wound healing and chronic wound development. We hypothesized that high OS levels lead to chronic wound development by promoting the colonization of biofilm-forming bacteria over commensal/beneficial bacteria. To test this hypothesis, we used our db/db^−/− mouse model for chronic wounds where pathogenic biofilms develop naturally after induction of high OS immediately after wounding. We sequenced the bacterial rRNA internal transcribed spacer (ITS) gene of the wound microbiota from wound initiation to fully developed chronic wounds. Indicator species analysis, which considers a species' fidelity and specificity, was used to determine which bacterial species were strongly associated with healing wounds or chronic wounds. We found that healing wounds were colonized by a diverse and dynamic bacterial microbiome that never developed biofilms even though biofilm-forming bacteria were present. Several clinically relevant species that are present in human chronic wounds, such as Cutibacterium acnes, Achromobacter sp., Delftia sp., and Escherichia coli, were highly associated with healing wounds. These bacteria may serve as bioindicators of healing and may actively participate in the processes of wound healing and preventing pathogenic bacteria from colonizing the wound. In contrast, chronic wounds, which had high levels of OS, had low bacterial diversity and were colonized by several clinically relevant, biofilm-forming bacteria such as Pseudomonas aeruginosa, Enterobacter cloacae, Corynebacterium frankenforstense, and Acinetobacter sp. We observed unique population trends: for example, P. aeruginosa associated with aggressive biofilm development, whereas Staphylococcus xylosus was only present early after injury. These findings show that high levels of OS in the wound significantly altered the bacterial wound microbiome, decreasing diversity and promoting the colonization of bacteria from the skin microbiota to form biofilm. In conclusion, bacteria associated with non-chronic or chronic wounds could function as bioindicators of healing or non-healing (chronicity), respectively. Moreover, a better understanding of bacterial interactions between pathogenic and beneficial bacteria within an evolving chronic wound microbiota may lead to better solutions for chronic wound management.

Towards a risk evaluation of workers' exposure to handborne and airborne microbial species as exemplified with waste collection workers

Bioaerosol exposure is associated with health problems. The aim of this study is to evaluate whether it is possible to assess the risks posed by waste collection workers' exposure through identification and characterization of bacterial and fungal species, to which the workers are exposed. Using MALDI-TOF MS, microorganisms in waste collection workers' exposure through air, hand, and contact with the steering wheel were identified. Fungi found in high concentrations from the workers' exposure were characterized for the total inflammatory potential (TIP), cytotoxicity, and biofilm-forming capacity. In total, 180 different bacterial and 37 different fungal species in the workers' exposure samples were identified. Some of them belong to Risk Group 2, e.g. Escherichia coli, Klebsiella oxytoca, Staphylococcus aureus, and Aspergillus fumigatus, some have been associated with occupational health problems e.g. Penicillium citrinum and P. glabrum and some are described as emerging pathogens e.g. Aureobasidium pullulans. The TIP of fungal species was dose-dependent. High TIP values were found for Penicillium italicum, P. brevicompactum, P. citrinum, and P. glabrum. Several species were cytotoxic, e.g. A. niger and P. expansum, while some, e.g. P. chrysogenum, did not affect the cell viability. Based on waste workers' average inhalation rate, they inhaled up to 2.3 × 10⁴ cfu of A. niger, 7.4 × 10⁴ cfu of P. expansum, and 4.0 × 10⁶ cfu of P. italicum per work day. Some species e.g. A. niger and P. citrinum were able to form biofilm. In conclusion, the workers were exposed to several species of microorganisms of which some to varying degrees can be evaluated concerning risk. Thus, some microorganisms belong to Risk Group 2, and some are described as causing agents of occupational health problems, emerging pathogens, or intrinsically antibiotic resistant. For some other species very little is known. The TIP, cytotoxicity, and ability to form biofilm of the dominating fungi support and expand previous findings. These parameters depended on the species and the dose, thus highlighting the importance of species identification and exposure level in the risk assessment of exposure.

Microbiota profiling with long amplicons using Nanopore sequencing: full-length 16S rRNA gene and whole rrn operon

Background: Profiling the microbiome of low-biomass samples is challenging for metagenomics since these samples often contain DNA from other sources, such as the host or the environment. The usual approach is sequencing specific hypervariable regions of the 16S rRNA gene, which fails to assign taxonomy to genus and species level. Here, we aim to assess long-amplicon PCR-based approaches for assigning taxonomy at the genus and species level. We use Nanopore sequencing with two different markers: full-length 16S rRNA (~1,500 bp) and the whole rrn operon (16S rRNA-ITS-23S rRNA; 4,500 bp). Methods: We sequenced a clinical isolate of Staphylococcus pseudintermedius, two mock communities (HM-783D, Bei Resources; D6306, ZymoBIOMICS™) and two pools of low-biomass samples (dog skin from either the chin or dorsal back), using the MinION™ sequencer 1D PCR barcoding kit. Sequences were pre-processed, and data were analyzed using the WIMP workflow on EPI2ME or Minimap2 software with rrn database. Results: The full-length 16S rRNA and the rrn operon were used to retrieve the microbiota composition at the genus and species level from the bacterial isolate, mock communities and complex skin samples. For the Staphylococcus pseudintermedius isolate, when using EPI2ME, the amplicons were assigned to the correct bacterial species in ~98% of the cases with the rrn operon marker, and in ~68% of the cases with the 16S rRNA gene. In both skin microbiota samples, we detected many species with an environmental origin. In chin, we found different Pseudomonas species in high abundance, whereas in dorsal skin there were more taxa with lower abundances. Conclusions: Both full-length 16S rRNA and the rrn operon retrieved the microbiota composition of simple and complex microbial communities, even from the low-biomass samples such as dog skin. For an increased resolution at the species level, using the rrn operon would be the best choice.

Microbiota profiling with long amplicons using Nanopore sequencing: full-length 16S rRNA gene and the 16S-ITS-23S of the rrn operon

Background: Profiling the microbiome of low-biomass samples is challenging for metagenomics since these samples are prone to contain DNA from other sources (e.g. host or environment). The usual approach is sequencing short regions of the 16S rRNA gene, which fails to assign taxonomy to genus and species level. To achieve an increased taxonomic resolution, we aim to develop long-amplicon PCR-based approaches using Nanopore sequencing. We assessed two different genetic markers: the full-length 16S rRNA (~1,500 bp) and the 16S-ITS-23S region from the rrn operon (4,300 bp). Methods: We sequenced a clinical isolate of Staphylococcus pseudintermedius, two mock communities and two pools of low-biomass samples (dog skin). Nanopore sequencing was performed on MinION™ using the 1D PCR barcoding kit. Sequences were pre-processed, and data were analyzed using EPI2ME or Minimap2 with rrn database. Consensus sequences of the 16S-ITS-23S genetic marker were obtained using canu. Results: The full-length 16S rRNA and the 16S-ITS-23S region of the rrn operon were used to retrieve the microbiota composition of the samples at the genus and species level. For the Staphylococcus pseudintermedius isolate, the amplicons were assigned to the correct bacterial species in ~98% of the cases with the16S-ITS-23S genetic marker, and in ~68%, with the 16S rRNA gene when using EPI2ME. Using mock communities, we found that the full-length 16S rRNA gene represented better the abundances of a microbial community; whereas, 16S-ITS-23S obtained better resolution at the species level. Finally, we characterized low-biomass skin microbiota samples and detected species with an environmental origin. Conclusions: Both full-length 16S rRNA and the 16S-ITS-23S of the rrn operon retrieved the microbiota composition of simple and complex microbial communities, even from the low-biomass samples such as dog skin. For an increased resolution at the species level, targeting the 16S-ITS-23S of the rrn operon would be the best choice.

Fluoroquinolone-resistant Achromobacter xylosoxidans clinical isolates from Serbia: high prevalence of the aac-(6')-Ib-cr gene among resistant isolates

The aim of this study was to evaluate the contribution of plasmid-mediated genes and efflux to fluoroquinolone resistance in collection of Achromobacter spp. gathered during a 3-year period. Susceptibility to ciprofloxacin and levofloxacin was tested by disk diffusion and microdilution tests for a collection of 98 Achromobacter spp. clinical isolates. Identification of fluoroquinolone-resistant isolates was performed by sequencing and phylogenetic analyses of the nrdA gene. Genetic relatedness among resistant isolates was determined by pulsed-field gel electrophoresis (PFGE) analysis. The influence of an H⁺ conductor cyanide m-chlorophenyl hydrazone (CCCP) and a resistance-nodulation-division-type efflux pump inhibitor phenylalanine-arginine beta-naphthylamide (PAβN) on minimal inhibitory concentration (MIC) value was evaluated by broth microdilution. The presence of the plasmid-mediated qnrA, qnrB, qnrC, qnrS, and aac-(6')-Ib-cr genes was investigated by PCR and sequencing. Achromobacter spp. isolates that were resistant or intermediately resistant to fluoroquinolones in disk diffusion tests (44/98) were subjected to microdilution. As a result, 20/98 isolates were confirmed to be resistant to ciprofloxacin while 10/98 was resistant to levofloxacin. CCCP decreased twofold MIC value for ciprofloxacin in six isolates and more than 16 times in one isolate, while MIC value for levofloxacin was decreased in all isolates (twofold to more than eightfold). Fluoroquinolone-resistant isolates were identified as A. xylosoxidans with the nrdA gene sequencing. PFGE revealed that resistant isolates belonged to seven different genotypes. Ten isolates belonging to four genotypes were positive for the aac-(6')-Ib-cr gene. Although resistance to fluoroquinolones was not widespread among analyzed isolates, detected contribution of efflux pumps and the presence of the aac-(6')-Ib-cr gene present a platform for emergence of more resistant strains.

Impact of delivery mode on the colostrum microbiota composition

BACKGROUND

Breast milk is a rich nutrient with a temporally dynamic nature. In particular, numerous alterations in the nutritional, immunological and microbiological content occur during the transition from colostrum to mature milk. The objective of our study was to evaluate the potential impact of delivery mode on the microbiota of colostrum, at both the quantitative and qualitative levels (bacterial abundance and microbiota network).

METHODS

Twenty-nine Italian mothers (15 vaginal deliveries vs 14 Cesarean sections) were enrolled in the study. The microbiota of colostrum samples was analyzed by next generation sequencing (Ion Torrent Personal Genome Machine). The colostrum microbiota network associated with Cesarean section and vaginal delivery was evaluated by means of the Auto Contractive Map (AutoCM), a mathematical methodology based on Artificial Neural Network (ANN) architecture.

RESULTS

Numerous differences between Cesarean section and vaginal delivery colostrum were observed. Vaginal delivery colostrum had a significant lower abundance of Pseudomonas spp., Staphylococcus spp. and Prevotella spp. when compared to Cesarean section colostrum samples. Furthermore, the mode of delivery had a strong influence on the microbiota network, as Cesarean section colostrum showed a higher number of bacterial hubs if compared to vaginal delivery, sharing only 5 hubs. Interestingly, the colostrum of mothers who had a Cesarean section was richer in environmental bacteria than mothers who underwent vaginal delivery. Finally, both Cesarean section and vaginal delivery colostrum contained a greater number of anaerobic bacteria genera.

CONCLUSIONS

The mode of delivery had a large impact on the microbiota composition of colostrum. Further studies are needed to better define the meaning of the differences we observed between Cesarean section and vaginal delivery colostrum microbiota.

Pseudobacteremia outbreak of biofilm-forming Achromobacter xylosoxidans - environmental transmission

Background

Achromobacter xylosoxidans (AX) is known for intrinsic resistance to disinfectants. Our laboratory routine surveillance system detected an unexpected rise in AX bloodstream infections in a 2200-bed hospital. An epidemiological investigation was conducted to find the source and disrupt further transmission.

Methods

Outbreak cases were defined as patients with at least one positive blood culture positive for AX from May 2014 to May 2015. Medical records were reviewed, affected wards, as well as the microbiology laboratory were audited. Additionally, microbiologic culture and biofilm staining for suspected antiseptic reusable tissue dispensers were performed, and isolated AX strains were typed using RAPD PCR and PFGE.

Results

During the outbreak period, AX were isolated from blood cultures from 26 patients. The retrospective cohort study did not reveal common risk factors. The clinical features of the case patients suggested a pseudobacteremia. The reusable tissue dispensers containing Incidin® Plus solution product were found to be contaminated with biofilm-forming AX. Typing of the isolates revealed that blood culture isolates were identical with the strains found in the dispensers.

Conclusions

After changing the usage of the product to single-use and educating staff, the outbreak was terminated. Contamination of dispensers occurred due to insufficient reprocessing, since biofilm disrupting steps were not included in the process.

Hospital Acquired Pneumonia Due to Achromobacter spp. in a Geriatric Ward in China: Clinical Characteristic, Genome Variability, Biofilm Production, Antibiotic Resistance and Integron in Isolated Strains

BACKGROUND

Hospital-acquired pneumonia (HAP) due to Achromobacter has become a substantial concern in recent years. However, HAP due to Achromobacter in the elderly is rare.

METHODS

A retrospective analysis was performed on 15 elderly patients with HAP due to Achromobacter spp., in which the sequence types (STs), integrons, biofilm production and antibiotic resistance of the Achromobacter spp. were examined.

RESULTS

The mean age of the 15 elderly patients was 88.8 ± 5.4 years. All patients had at least three underlying diseases and catheters. Clinical outcomes improved in 10 of the 15 patients after antibiotic and/or mechanical ventilation treatment, but three patients had chronic infections lasting more than 1 year. The mortality rate was 33.3% (5/15). All strains were resistant to aminoglycosides, aztreonam, nitrofurantoin, and third- and fourth-generation cephalosporins (except ceftazidime and cefoperazone). Six new STs were detected. The most frequent ST was ST306. ST5 was identified in two separate buildings of the hospital. ST313 showed higher MIC in cephalosporins, quinolones and carbapenems, which should be more closely considered in clinical practice. All strains produced biofilm and had integron I and blaOXA-114-like . The main type was blaOXA-114q . The variable region of integron I was different among strains, and the resistance gene of the aminoglycosides was most commonly inserted in integron I. Additionally, blaPSE-1 was first reported in this isolate.

CONCLUSION

Achromobacter spp. infection often occurs in severely ill elders with underlying diseases. The variable region of integrons differs, suggesting that Achromobacter spp. is a reservoir of various resistance genes.

Achromobacter xylosoxidans Bacteremia and Cellulitis: A Report of a Case

Achromobacter xylosoxidans is a rare, opportunistic infection most commonly encountered in immunocompromised patients during hospitalization. Primary uncomplicated bacteremia, catheter-associated infections, and pneumonia have been reported as the most common clinical presentations; skin and soft tissue infections from A. xylosoxidans are rare. We describe a case of A. xylosoxidans presenting as cellulitis and bacteremia in an immunocompromised patient.

Characterization of two Achromobacter xylosoxidans isolates from patients with pertussis-like symptoms

Objective

To characterize two Achromobacter xylosoxidans recovered from 2 patients diagnosed with pertussis during a Bordetella pertussis surveillance program.

Methods

Nasopharyngeal swabs from 2 children under 1 year of age with clinical suspicion of pertussis were analyzed by culture and PCR.

Results

Two Achromobacter xylosoxidans A8, closely related to Bordetella spp. were recovered from 2 patients diagnosed of pertussis, both carrying the ptxA gene and IS418 the pertussis toxin encoding gene. Subsequently, antibiotic susceptibility was evaluated by disk-diffusion method and by PCR.

Conclusions

Although more detailed studies are needed, the present data highlight the possibility that Achromobacter xylosoxidans, closely related Bordetella pertusssis microorganisms and not covered under the vaccine umbrella, might also result in cases of whooping cough. Thereby further surveillance is necessary to determine the extension and relevance of their pathogenic role in order to discriminate their real public health implication.

Alcaligenes faecalis: an unusual cause of skin and soft tissue infection

Skin and soft tissue infection (SSTI) due to Alcaligenes faecalis is very rare and has never been studied. The aim of the present study was to investigate the clinical and microbiological characteristics of this infection. We conducted a retrospective review of 5 cases that occurred at our institution over a period of 6 years. All patients had underlying diseases, and infection was secondary to vascular disease or recent surgery in 4 of them. The most common clinical presentations were vascular ulcer infection and surgical site infection. The clinical outcome was uniformly good after treatment, except in 1 patient. In conclusion, A. faecalis should be considered a potential pathogen of SSTI, particularly in patients with vascular diseases or after surgery. The history of contact with water or aqueous solutions should be investigated in all cases. The clinical outcome is usually good, but treatment can be difficult in some cases due to the high level of resistance to commonly used antibiotics.