Anaerobic Isolates Research Articles

Utilization of MALDI-TOF MS in the etiological diagnosis of deep-seated anaerobic bacterial infections

PurposeDeep-seated abscesses can be caused by a wide array of bacteria in various anatomical sites, the precise identification of which is crucial for implementing organism-specific treatments which can reduce morbidity and mortality. MALDI-TOF MS is a powerful proteomic method for the swift and accurate identification of anaerobic organisms. The aim of this study was to investigate deep-seated infections by MALDI-TOF MS (in comparison to VITEK®2 ANC ID card and phenotypic biochemical tests) and to determine the susceptibility pattern of identified microorganisms. Materials and methodsA total of 104 samples from patients suspected of deep-seated infections were aseptically collected and subjected to microscopy, aerobic/anaerobic cultures and subsequent identification via MALDI-TOF MS followed by antimicrobial susceptibility testing. Anaerobic bacteria were also identified using the VITEK-2 system and phenotypic biochemical tests. ResultsOut of the 104 samples tested, 41.3 % (43/104) showed positive results, predominantly in pus specimens (88 %). Mixed infections were found in 21 % of the positive cases. Of the 52 organisms identified from positive specimens, 19.2 % (10/52) were obligate anaerobes, with Bacteroides fragilis group being the most prevalent, followed by both Clostridium perfringens and Clostridium sporogenes respectively. Escherichia coli was observed to be the most common facultative anaerobic isolate. All obligate anaerobes were successfully identified to the species level via MALDI-TOF MS. In contrast, the VITEK®2 ANC ID card identified only 40 % (4/10) anaerobic bacteria to the species level. All obligate anaerobic organisms showed 100 % susceptibility to metronidazole, vancomycin and ertapenem. 25 % of the Bacteroides spp. and 50 % of Clostridium perfringens isolates were found to be resistant to clindamycin. ConclusionMALDI-TOF MS proves as a beneficial diagnostic tool for bacterial identification, eliminating the labour-intensive and time consuming conventional microbiological methods. Its accuracy of bacterial detection further helps in combating antibiotic resistance and improving patient outcomes in deep-seated infections.

Bacterial profile of wound site infections and evaluation of risk factors for sepsis among road traffic accident patients from Apex Trauma Centre, Northern India.

Background. Among the most significant yet often ignored health issues worldwide are trauma and accidental injuries. India accounts for 11% of global deaths in road accidents, the highest in the world, according to the World Bank report. There are limited data about the bacterial contamination of road traffic accident (RTA) wounds and their antibiotic susceptibility patterns. Materials and Methods. This prospective study was conducted in a tertiary care centre in northern India from January 2023 to January 2024. Wound deep swabs or aspirates were collected from RTA patients with traumatic injuries at different time intervals. Gram stain and culture were performed, and positive aerobic culture was subjected to antibiotic susceptibility testing. Organism identification was done using MALDI-TOF MS and routine biochemical tests. Blood samples were also collected to rule out bloodstream infections during follow-up if the patient became febrile or showed symptoms of systemic infection. Sepsis was defined in those patients who had two or more scores in the systemic inflammatory response syndrome criteria with a positive microbiological culture. Risk factors were evaluated for sepsis on the basis of the patient's vitals, injury characteristics, procalcitonin, Glasgow Coma Scale (GCS) score, need for mechanical ventilation and complete blood count, which were obtained from the patient's admission file. Results. A total of 189 wound samples were collected, of which 99 (52.38%) samples showed the growth of microorganisms. The aerobic isolates included 69 (69.69%) Gram-negative bacilli, of which the majority were Klebsiella pneumoniae, 28 (28.28%) Gram-positive cocci, of which the majority were Staphylococcus aureus and 2 (2.02%) anaerobic isolates. Among the Gram-negative isolates, none of the isolates were resistant to colistin. All S. aureus isolates were susceptible to vancomycin, teicoplanin and levonadifloxacin. Sepsis developed in 50 (26.45 %) patients. Significant risk factors evaluated for sepsis were a raised procalcitonin level, a low GCS score, a higher injury severity score, the need for mechanical ventilation and a raised quick sequential organ failure assessment score. Conclusion. It is essential to ascertain the profile of microorganisms isolated from RTA wounds in order to reduce antibiotic resistance and deliver efficient treatment.

Antimicrobial susceptibility of Clostridium botulinum group III field strains isolated in Europe from animal outbreaks

Neurotoxins produced by Clostridium (C.) botulinum group III are responsible for the majority of botulism outbreaks occurring in animals and in this study we report the drug susceptibility of 71 field strains.The minimum inhibitory concentration (MIC) of 13 antimicrobials was established through the agar dilution method. The MIC50 matched or differed for one or two dilutions from MIC90 of the same antimicrobial, showing a unimodal distribution of the MIC values, irrespective of the geographical origin, the animal source and the toxinotype of the strain. Beta-lactams and rifampin showed the lowest MIC values, while gentamicin, polymyxin B and sulfamethoxazole showed the highest MICs. As for similar studies conducted in human botulism, the results could be helpful to avoid the administration of antimicrobials that could worsen the health condition of the affected animals and to develop selective media for the isolation of these fastidious anaerobes. Indeed, the isolation of the strain from affected animals and from environmental samples is important to perform epidemiological studies based on the genetic characterization and to produce tailor-made vaccines.

An Eleven-Year Retrospective Survey of Anaerobic Bloodstream Infection in Adults in a General Hospital.

During conditions accompanied by the disruption of normal mucosal barriers, anaerobic bacteria, which a part of normal human mucosal microflora, may cause various infections. In this study, clinical features of anaerobic bloodstream infections (BSI) in a general hospital in China were investigated. Patients with anaerobic BSI were retrospectively enrolled between 2012 and 2022. Demographic data, clinical manifestations, antibiotic treatments, and disease outcomes were analyzed. In total, 391 anaerobic bacterial strains were isolated from 381 patients aged older than 11 years of age. Given that medical records of 47 patients were missing, 334 patients were included in the clinical investigation. Patients with anaerobic BSI included in the study were predominantly older than 50 years of age. Intra-abdominal infections were the most common source of anaerobic BSI (59%), followed by those of the female genital tract (10.2%) and lower respiratory tract (7.2%). Among the isolates, Bacteroides and Clostridium spp. were the most frequently isolated anaerobes. Most of the patients received antibiotic therapy. The crude mortality was 4.5%. The detection rate of anaerobic BSI in Ningxia, China, remained relatively stable from 2012 to 2022. These results provide a reference for the diagnosis and empirical treatment of anaerobic BSI in this region of China. Continuous mul-ticenter studies should be conducted to monitor the incidence of anaerobic BSI and drug resistance of anaerobic isolates to improve the treatment outcomes of patients.

Third Kuwaiti Multicenter Survey of Antibiotic Susceptibility of Anaerobic Bacteria: A Comparative Analysis of 20-Year Data.

Objective: This study aimed to evaluate antibiotic susceptibility and antimicrobial resistance trends among clinically significant anaerobes in Kuwait hospitals from 2013 to 2022, comparing these findings with data from 2002 to 2012. Methods: The study prospectively collected 2,317 anaerobic isolates from various body sites across four Kuwaiti hospitals between January 2013 and December 2022. The minimum inhibitory concentrations for 11 antianaerobic antibiotics were determined using E-test methodology. The study analyzed trends and resistance rates across two periods: 2013-2017 and 2018-2022, using statistical analysis for resistance comparison. Results: Of the 2,317 isolates, most were from wounds (42.2%), fluids (28.0%), and tissues (20.5%). Bacteroides fragilis was the most common pathogen (34.0%), followed by Prevotella bivia (13.4%). Over 90% of isolates were susceptible to imipenem, meropenem, tigecycline, and metronidazole, whereas lower susceptibility was observed for penicillin, amoxicillin-clavulanic acid, and clindamycin. Notable differences in resistance profiles since 2002 were observed, especially in amoxicillin-clavulanic acid, piperacillin, piperacillin-tazobactam, and clindamycin. Conclusion: Owing to detected resistance to all antibiotics, susceptibility testing for anaerobic isolates is recommended in severe infections to ensure effective antimicrobial therapy. Continuous surveillance is crucial for developing antibiotic policies to manage invasive anaerobic infections.

Reliability of superficial swab culture results compared with deep wound culture results in Fournier’s gangrene: a retrospective study

ObjectivesTo compare isolates from deep wound and superficial swab cultures to evaluate the detectability of pathogens by each culture in Fournier’s gangrene; and evaluate the association between microorganisms isolated from deep wounds and those isolated from blood or urine. MethodsPatients with Fournier’s gangrene who underwent debridement between October 2006 and January 2023 were retrospectively reviewed. In addition to comparing the isolates from deep wound cultures at initial debridement with those from superficial swab, blood, and urine cultures, the relationship between the traits of the organisms from deep wounds and patient disease severity and prognosis was examined. ResultsAmong 25 patients, deep wound and superficial swab cultures were obtained from 25 and 18 patients, respectively. The frequency of anaerobic isolates was significantly lower in the superficial cultures than in the deep wound cultures (31/76 versus 13/56, p = 0.034). Bacteria not isolated from deep wounds were isolated from superficial cultures in 55.6 % of the patients; the concordance rate between deep and superficial cultures was 27.8 % (5/18). The positive rates of blood and urine cultures were 20.8 % and 35.7 %, respectively; all isolates from the urine and blood cultures reflected the results of the deep wound culture. No significant association was observed between the severity or mortality and the type of causative bacteria. ConclusionsSuperficial swab cultures cannot be substituted for deep wound cultures in Fournier’s gangrene. Although the positivity rates for blood and urine cultures were not high, they were helpful in determining antibiotic de-escalation.

An updated description of bacterial pneumonia in adult horses and factors associated with death.

Available descriptive studies on equine pneumonia are outdated or focus on specific horse or bacterial populations. To describe the clinical presentation and bacterial isolates of adult horses with bacterial pneumonia and identify factors associated with death. One hundred sixteen horses >2 years old with bacterial pneumonia. Retrospective case series. Data regarding history, physical examination, clinicopathologic features, treatment, bacterial culture and sensitivity, and outcome were collected and analyzed retrospectively. Historical risk factors were present for 60% of cases, whereas abnormal vital signs on intake were present for <50%. Most horses (58%) underwent at least 1 change of antimicrobial treatment, and 67% received the highest-priority critically important antimicrobials. Streptococcus zooepidemicus was the most isolated bacteria (44%), followed by Escherichia coli (19%), Klebsiella spp. (18%), other Streptococcus species (17%), and Bacillus spp. (13%). Fusobacterium spp. were the most common anaerobic isolates (11%). Antimicrobial susceptibility varied widely. Survival to discharge was 73%. Heart rate at presentation (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.008-1.17, P = .03) and higher creatinine (OR 14.1, 95% CI 1.56-127.6, P = .02) increased the risk of death. Higher lymphocyte count (OR 0.27, 95% CI 0.08-0.94, P = .04) reduced risk. Contrasting older literature, Fusobacterium spp. were the most common anaerobes. Streptococcus zooepidemicus remained the most common isolate and was predictably susceptible to penicillin. Antimicrobial susceptibility was otherwise variable and broad applicability is limited as this was a single-center study. Increased risk of death associated with tachycardia and abnormally high serum creatinine concentration is consistent with previous studies.

Diagnosis and outcome of odontogenic abscesses in client-owned rabbits (Oryctolagus cuniculus): 72 cases (2011-2022).

To characterize the epidemiologic features of rabbits with odontogenic abscesses. 72 client-owned rabbits. The medical record database of a veterinary teaching hospital was searched to identify rabbits with odontogenic abscesses characterized by a palpable facial mass and confirmed via CT scan. Data reviewed included age, breed, presenting complaint, abscess location, bacterial culture results, treatment, and outcome. Lop-eared rabbits were the most common breeds affected (20/72 [28%]), and mini lop rabbits were significantly overrepresented. The mandibular quadrants were more frequently affected (65/92 [71%]), and osteomyelitis was a common comorbidity on CT (53/72 [74%]). The most common aerobic and anaerobic isolates were Streptococcus spp (17/40 [43%]) and Fusobacterium spp (10/22 [45%]), respectively. Systemic antibiotic therapy alone was performed in 35 of 62 (56%) treated cases, with documented resolution in 25%. Abscess packing with antibiotic-soaked gauze in conjunction with systemic antibiotic therapy was performed in 20 of 62 (32%) treated cases. Resolution of the odontogenic abscesses with this treatment protocol was documented in 17 of 20 (85%) cases. The number of packing procedures used to obtain resolution of infection was 4 (IQR, 3 to 5). A combination of the abscess-packing technique, which avoids extensive surgery and extraction of the involved elodont teeth, with systemic antibiotic therapy can be an effective treatment option for rabbits with palpable odontogenic abscesses and can result in a high cure rate comparable to more invasive surgical treatments. Antibiotic treatment alone is not recommended, as it has a low chance of abscess resolution.

Antibacterial and hemocompatibility potentials of nano-gold-cored alginate preparation against anaerobic bacteria from acne vulgaris

Acne is a prevalent dermatological disease, with high global incidence, and is a health menace. The current study aimed to isolate and characterize the anaerobic bacteria responsible for the condition. Causes of a total of 70 acne-based bacterium isolates obtained from patients of mild, moderate, and severe acne, 24 were Clostridium innocuum, 21 were Lactobacillus plantarum, 13 were Anaerococcus prevotii, and 12 were Peptoniphilus asaccharolyticus. Nearly 69% of males were suffering, while the rest were females at 31%. The 15–30 years old age group was the most affected. The gold/alginate nanoparticles’ nanopreparation (GANPs) produced from chloroauric acid and sodium alginate was an effective treatment against the acne conditions under the experimental conditions. The nanopreparation exhibited significant inhibitory activity against anaerobic bacterial isolates, with a minimum inhibitory concentration of 200 µg/ml for A. prevotii and P. asaccharolyticus, and 400 µg/ml for C. innocuum and L. plantarum. The in vitro efficacy of the GANPs on human blood parameters was also assessed. The concurrent results suggested potential antibacterial activity and hemocompatibility of the product, which has promise to be used as a successful antibacterial agent for acne.

Prevalence of anaerobic bacteria in surgical site infections in Lagos University Teaching Hospital.

Surgical site infection (SSI) is the second most common cause of nosocomial infection, after urinary tract infection. Sequelae of SSI include increased healthcare costs and worse patient outcomes. There is a paucity of research studies on the impact of anaerobic organisms on SSIs in Nigeria. The aim of this study was to determine the role of anaerobic bacteria in SSI encountered at the Lagos University Teaching Hospital (LUTH). A total of 438 patients were consecutively recruited into this study from general surgery, obstetrics and gynaecology and paediatric units of the LUTH from 1 July through 31 December 2019. Two surgical wound specimens were collected from all patients with suspected SSIs. One was for anaerobic culture using Brucella blood agar incubated in an anaerobic jar that secured anaerobiosis using the anaerobic gas pack. The other swab was used for aerobic culture on blood agar incubated on air at 37oC. Identifications and antibiotic sensitivity testing were performed according to standard laboratory procedures. The overall incidence of SSI in the study was 12.3%. The incidence of anaerobic SSI was 1.1%. The distribution of anaerobic infections by medical specialty unit was as follows; general surgery (1.6%), obstetrics and gynaecology (0.8%) and paediatrics (0.9%). Bacteroides species was the only anaerobic isolate. The risk factors associated with the development of SSI by multiple logistic regression analysis were duration of surgery greater than 2 h (OR 1.418; 95% CI 1.834-9.286; P = 0.001) and NNIS risk index 2 and 3 - (OR 2.165; 95% CI 2.366-32.086; P = 0.001). The prevalence of anaerobic SSI was 1.1%. Duration of surgery greater than 2 h and NNIS risk index 2 and 3 were independent predictors of SSI.

The addition of anaerobic fungi isolates from buffalo rumen to increase fiber digestibility, fermentation, and microbial population in ruminants

Abstract. Agustina S, Wiryawan KG, Suharti S, Meryandini A. 2024. The addition of anaerobic fungi isolates from buffalo rumen to increase fiber digestibility, fermentation, and microbial population in ruminants. Biodiversitas 25: 107-115. Rumen microbes have an important role in the rumen. Anaerobic fungi are microbes needed in the forage digestion process in the rumen. The addition of microbes, particularly anaerobic fungi is essential to increase the digestibility of forage within rumen. Therefore, this study aimed to evaluate the addition of anaerobic fungi isolates from buffalo rumen to increase fiber digestibility, fermentation, and microbial population in sheep rumen. The in vitro tests were carried out using the Tilley and Terry method, using elephant grass and rice straw as tested forage. Piromyces sp. (F1, and F3), Caecomyces sp. (F2, and F5), and Neocallimastix frontalis (F4) isolates from buffalo rumen were used as tested anaerobic fungi. The result showed that the addition of anaerobic fungi isolates from buffalo rumen significantly affected fiber digestibility (Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), cellulose and hemicellulose) except lignin digestibility. The addition of N. frontalis had higher fiber digestibility which is 49.02% NDF digestibility, 42.11% ADF digestibility, 44.28% hemicellulose digestibility, and 38.60% cellulose digestibility. Furthermore, N. frontalis also significantly increased In vitro Dry Matter Digestibility (IVDMD), In vitro Organic Matter Digestibility (IVOMD), ammonium (NH3) production, total Volatile Fatty Acid (VFA) production, and microbial population compared to Piromyces sp., and Caecomyces sp. In conclusion, anaerobic fungus type N. frontalis showed promising potential to be used as a ruminant probiotic due to its superior effect on fiber digestibility, fermentation, and microbial population compared to Caecomyces sp. and Piromyces sp.

Epidemiologia molecular do Clostridioides difficile obtido de amostras de fezes de animais selvagens no Brasil

ABSTRACT: Clostridioides difficile is a strictly anaerobic, spore-forming Gram-positive bacterium associated with diarrhea, known as C. difficile infection (CDI). In domestic animals, C. difficile is considered an important pathogen mostly in pigs and horses, but there are also reports in other domestic species. In wild animals, the epidemiology of C. difficile is largely unknown, and the role of the bacterium as a cause of diarrhea is unclear. The aim of this study was to determine the prevalence of C. difficile in the feces of wild animals referred to the Center of Medicine and Research in Wild Animals (CEMPAS). Fecal samples obtained from 100 animals of 34 different species were subjected to qPCR for the detection of the C. difficile 16S rRNA gene and two major toxin genes (tcdA and tcdB) and to anaerobic bacterial isolation. A total of 63 animals (63%) were positive for C. difficile by qPCR, and 16 isolates were recovered. The opossum (Didelphis spp.) had the highest number of positive animals in both tests (from 21 samples, 19 were qPCR positive, and four isolates were recovered). Three toxigenic strains (RT 002, 004, and 014), all previously described as infecting humans and animals, were isolated in the following species: bearded dragon (Pogona vitticeps), pampas fox (Lycalopex vetulus), and marmoset (Callithrix sp.). The presence of C. difficile in the feces of wild animals highlights the importance of wildlife as potential carriers of infection for production animals or humans.

In vitro activity of delafloxacin against anaerobic bacteria compared with other antimicrobials

The aim of this study was to describe the in vitro activity of delafloxacin against 230 anaerobic isolates and compare it with the activity of other antimicrobials used against infections caused by anaerobic microorganisms. Minimal inhibitory concentrations (MICs) were lower for delafloxacin than for all other antibiotics tested with the exception of piperacillin-tazobactam and meropenem against Gram-positive anaerobic cocci. Only two (0.8 %) isolates of Bacteroides spp. showed a MIC ≥4 μg/mL. With some exceptions, the present results show lower MICs for delafloxacin in comparison to the other antibiotics used against anaerobes.

Fifty years devoted to anaerobes: historical, lessons, and highlights.

Renew interest and enthusiasm for anaerobes stem from both technological improvements (culture media, production of an adequate anaerobic atmosphere, identification methods) and greater awareness on the part of clinicians. Anaerobic infections were historically treated empirically, targeting the species known to be involved in each type of infection. Prevotella, fusobacteria, and Gram-positive cocci (GPAC) were considered responsible for infections above the diaphragm whereas for intra-abdominal infections, Bacteroides of the fragilis group (BFG), GPAC and clostridia were predominantly implicated. The antibiotic susceptibility of anaerobes was only taken into consideration by the clinician in the event of treatment failure or when faced with infections by multidrug-resistant bacteria (MDR). The evolution of antibiotic resistance together with clinical failures due to the absence of detection of hetero-resistant clones has resulted in a greater need for accessible antibiotic susceptibility testing (AST) and disc diffusion method. Improved isolation and identification of anaerobes, along with the availability of accessible and robust methods for performing AST, will ensure that treatment, whether empirical or guided by an antibiogram, will lead to better outcomes for anaerobic infections.

Long-term systemic antibiotics and surgical treatment can be an effective treatment option for retrobulbar abscesses in rabbits (Oryctolagus cuniculus): 21 cases (2011-2022).

To characterize the epidemiologic features of rabbits with retrobulbar abscesses, including the clinical signs, diagnosis, treatment, and outcome. 21 client-owned rabbits. The medical record database of a veterinary teaching hospital was searched from 2011 to 2022 for records of rabbits diagnosed with retrobulbar abscesses by CT. Data reviewed included age, breed, presenting complaint, association with an odontogenic infection, aerobic and anaerobic culture results, treatment, and outcome. The primary presenting complaint was exophthalmos (19/21 [90%]). Most cases (15/21 [71%]) were associated with an odontogenic infection. Dental disease, not associated with a retrobulbar abscess (14/21 [67%]), was a common comorbidity on CT. The most common aerobic and anaerobic isolates were Streptococcus intermedius (5/12 [42%]) and Fusobacterium nucleatum (2/12 [17%]), respectively. Surgical treatment combined with long-term systemic antibiotic therapy was performed in 9 of 21 (43%) cases. It included intraoral tooth extraction (4/9 [44%]) versus extraoral peribulbar abscess lancing with either abscess packing with antibiotic-soaked gauze (3/9 [33%]) or surgical abscess debridement (2/9 [22%]). Resolution of the clinical signs with no recurrence for at least 6 months occurred in 7 of 9 (78%) surgically treated cases. Medical treatment with long-term systemic antibiotic therapy was performed in 4 of 21 (19%) cases, and 3 of 4 (75%) resolved. Due to poor prognosis or financial concerns, euthanasia was performed or recommended in 8 of 21 (38%) cases. On the basis of the data from this study, retrobulbar abscesses in rabbits carry a guarded prognosis. When intraoral and extraoral surgical treatment options combined with systemic antibiotic therapy were used, it resolved clinical disease in most cases.

Causative microbes and antibiotic susceptibility of acute appendicitis in adults and children

In recent years, some studies have found that acute uncomplicated appendicitis can be treated with antibiotics alone. Because of the lack of relevant research on treating acute appendicitis in Taiwan, this study investigated the microbiological characteristics of acute appendicitis to permit accurate empirical antibiotic use for uncomplicated appendicitis. In this single-center retrospective cohort study, patients listed in the Taiwan National Health Insurance Research Database with a discharge diagnosis of acute appendicitis were identified. Data for bacterial specimens and antibiotic susceptibility tests among patients treated at Tri-Service General Hospital between January 2016 and December 2021 were analyzed. Among 2805 patients diagnosed with acute appendicitis, 167 (6%) were <18 years old. The culture positivity rates among children and adults were 33% and 18%, respectively. In total, 367 aerobes and 207 anaerobes were isolated. The predominant aerobic gram-positive coccus was viridans group streptococci (8.9%), the most common aerobic gram-negative bacillus was Escherichia coli (27.9%), and the most common anaerobic microorganism was Bacteroides spp. (27.7%). The results of antibiotic susceptibility testing of the predominant microorganisms revealed that 86.3% of gram-positive aerobes were susceptible to ampicillin, 76.3% of gram-negative aerobes were susceptible to gentamicin, and all anaerobic isolates were susceptible to metronidazole. Triple first-line antibiotic combination therapy, including ampicillin, gentamicin, and metronidazole, remains highly effective against the pathogens that cause acute appendicitis.

Comparison of the Etest and Sensititre methods for anaerobe susceptibility testing

Background and Aims: Antimicrobial susceptibility testing of anaerobic clinical isolates is of paramount importance for patient therapy and resistance monitoring. In our laboratory the MIC gradient Etest method and broth microdilution with Sensititre trays are used for susceptibility testing of anaerobes and the aim of this study was to compare the two methods on a panel of anaerobes routinely isolated from patients in the province of Bolzano, Italy. Materials and Methods: Totally, 74 non-repetitive Gram-positive and Gram-negative patient isolates were tested with Etest strips on Fastidious Anaerobe Agar (F.A.A.) and with Sensititre trays, according to manufacturer’s instructions. Interpretation of MICs was by EUCAST or CLSI criteria, resistance percentages were calculated and Categorical Agreement (CA) and Essential Agreement (EA) between the two methods were determined. Results: Of the 74 isolates, 68 (91.9%) grew on both systems and agreement for these was compared in the study. CA for all isolates was ≥90% for all tested antibiotics except moxifloxacin, whereas EA was generally lower. Resistance was generally low, except for clindamycin in all isolates and tigecycline in Gram-negatives. In our study Etest was a superior and more handy method. Conclusions: To conclude, we believe the Etest method is more suitable for routine diagnostic laboratory usage. Nevertheless, multicenter studies are required to evaluate the two methods for anaerobic susceptibility testing.

Recent Trends in Antimicrobial Resistance among Anaerobic Clinical Isolates.

Anaerobic bacteria are normal inhabitants of the human commensal microbiota and play an important role in various human infections. Tedious and time-consuming, antibiotic susceptibility testing is not routinely performed in all clinical microbiology laboratories, despite the increase in antibiotic resistance among clinically relevant anaerobes since the 1990s. β-lactam and metronidazole are the key molecules in the management of anaerobic infections, to the detriment of clindamycin. β-lactam resistance is usually mediated by the production of β-lactamases. Metronidazole resistance remains uncommon, complex, and not fully elucidated, while metronidazole inactivation appears to be a key mechanism. The use of clindamycin, a broad-spectrum anti-anaerobic agent, is becoming problematic due to the increase in resistance rate in all anaerobic bacteria, mainly mediated by Erm-type rRNA methylases. Second-line anti-anaerobes are fluoroquinolones, tetracyclines, chloramphenicol, and linezolid. This review aims to describe the up-to-date evolution of antibiotic resistance, give an overview, and understand the main mechanisms of resistance in a wide range of anaerobes.

Biosurfactant-Producing Bacteria and Microbial Analysis in Mae Soon Reservoir, Fang Oil Field, Chiang Mai, Thailand

Microbial Enhanced Oil Recovery (MEOR) is an effective alternative method for oil recovery in reservoirs using microorganisms or their secondary metabolites. This research aimed to evaluate the indigenous bacteria from Mae Soon reservoir by culture-dependent and culture-independent methods and to investigate the potential of biosurfactant-producing bacteria using a drop-collapsed assay. Indigenous bacteria were isolated from the oil sands of the reserved core of Mae Soon reservoir using fi ve different media (nutrient, Luria-Bertani, mineral salt, tryptic soy, and peptone yeast extract). Fifty-four facultative anaerobic bacterial isolates were obtained. Seven isolates showed their potential as biosurfactant producers in the drop-collapse assay. Based on 16S rRNA gene analysis, six of the biosurfactant-producing bacterial isolates belonged to the species Bacillus licheniformis and one belonged to the species B. subtilis. The biosurfactant producers and microbial community in the oil sands were determined using Denaturing Gradient Gel Electrophoresis (DGGE). Interestingly, DGGE bands corresponding to bacteria belonging to the genus Geobacillus sp. were detected. Overall, the results obtained from this work showed that indigenous bacteria in Mae Soon reservoir oil well were prospective for use in MEOR.

Correction to: In vitro activity of sulopenem and comparator agents against Enterobacterales and anaerobic clinical isolates collected during the SENTRY Antimicrobial Surveillance Program

Correction to: <i>In vitro</i> activity of sulopenem and comparator agents against Enterobacterales and anaerobic clinical isolates collected during the SENTRY Antimicrobial Surveillance Program