Bacterial Isolation Rate Research Articles

Prevalence and Antimicrobial Susceptibility Patterns of Wound and Pus Bacterial Pathogens at a Tertiary Care Hospital in Central Riyadh, Saudi Arabia

The long history and extensive use of antibiotics have caused resistant bacterial pathogens to emerge, increasing mortality and morbidity. The current study was designed to see the prevalence of aerobic bacterial isolates with their antimicrobial resistance pattern from out- and inpatients requested for wound or pus culture. Retrospective study conducted at a tertiary care hospital in central Riyadh from January 2023 to December 2023. Samples were collected and inoculated onto the appropriate media following standard guidelines. Bacterial pathogens were identified by the Vitek2 compact system. Antimicrobial susceptibility was tested using the Kirby–Bauer disk diffusion method as well as by MIC determination through the Vitek2 compact. A total of 1186 subjects were included in the study with a bacterial isolation rate of 691 (58.3%). Out of these, 155 positive cultures had incomplete information or anaerobic or fungal growth and were excluded from the study. With a slight female predominance (54.9%), the majority of subjects (72.2%) were outpatients, and over half of the isolates (55.2%) were Gram-positive. The most common isolate was Staphylococcus spp. (44.4%), followed by E. coli (13.6%) and P. aeruginosa (12.9%). The highest resistance was reported against penicillin followed by fusidic acid against Gram-positive bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in 40.5% of Staphylococcus aureus (S. aureus) isolates. Amikacin was the most susceptible antibiotic against all Gram-negative isolates. MDR Gram-negative bacteria accounted for 51.9% of wound infection isolates (95% CI: 45.95 to 58.33) while 6.3% (95% CI: 4.39 to 8.86) were XDR (nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories). A high prevalence of bacterial isolates, with S. aureus as the predominant pathogen, showed high rates of multidrug resistance. This highlights the importance of monitoring antibiotic choices for prophylaxis and treatment in the study area.

The role of intraoperative swab during appendectomy in patients with uncomplicated and complicated appendicitis

IntroductionBacteria play an important role not only in pathogenesis of appendicitis but also in the postoperative course of patients. However, the usefulness of an intraoperative swab during appendectomy is controversial. The primary aim of this study was to investigate the impact of intraoperative swab during appendectomy on the postoperative outcome in patients with uncomplicated and complicated appendicitis.MethodsA retrospective analysis was conducted on a consecutive series of 1570 adult patients who underwent appendectomy for acute appendicitis at the University Hospital Erlangen between 2010 and 2020. Data regarding the intraoperative swab were collected and analyzed for the entire cohort as well as for patients with uncomplicated and complicated appendicitis.ResultsAn intraoperative swab was taken in 29% of the cohort. The bacterial isolation rate in the obtained intraoperative swabs was 51%, with a significantly higher rate observed in patients with complicated appendicitis compared to those with uncomplicated appendicitis (79% vs. 35%, p < 0.001). The presence of a positive swab was significantly associated with worse postoperative outcomes, including higher morbidity, increased need for re-surgery, and longer hospital stay, when compared to patients without a swab or with a negative swab. A positive swab was an independent risk factor for postoperative morbidity (OR 9.9 (95% CI 1.2–81.9), p = 0.034) and the need for adjustment of postoperative antibiotic therapy (OR 8.8 (95% CI 1.1–72.5), p = 0.043). However, a positive swab resulted in postoperative antibiotic therapy adjustment in only 8% of the patients with bacterial isolation in the swab.ConclusionThe analysis of swab samples obtained during appendectomy for acute appendicitis can help identify patients at a higher risk of a worse postoperative outcome. However, the frequency of antibiotic regime changes based on the swab analysis is low.

Distribution and Drug Resistance of Bacterial Infection in Hospitalized Patients at the Respiratory Department before and after the COVID-19 Pandemic in Guangzhou, China.

Since COVID-19 might have a lasting impact on global public health, it is crucial to analyze its effect on drug-resistant bacterial infections in the respiratory system for the prevention and control of hospital infections. This work aimed to investigate the impact of the COVID-19 outbreak on the clinical distribution and antibiotic resistance of bacterial infection among hospitalized patients in the respiratory unit in order to establish strategies to control antibiotic-resistant infections. Electronic clinical data registry records from 2018 to 2022 were retrospectively analyzed. A total of 36,829 clinical specimens, including sputum, bronchoalveolar lavage fluid, blood, and urine, were collected from 16,073 patients admitted to the Guangzhou First People's Hospital from January 2018 to December 2022. Among them, 2209 samples were culture-positive. The bacterial isolation rates of different types of samples showed a similar trend from 2019 to 2022, with an increase in 2020 and 2022 and a decrease in 2021. Different bacterial species were separated from different types of samples. The most reported pathogens were identified in sputum samples. Gram-positive isolates were prevalent in urine samples, while Gram-negative bacilli were the predominant pathogenic bacteria isolated from respiratory tract and blood samples. Pseudomonas aeruginosa (P. aeruginosa), Acinetobacter baumannii (A. baumannii) complex, and Klebsiella pneumoniae (K. pneumoniae) were the most abundant Gram-negative bacteria in sputum samples, of which A. baumannii complex had the highest resistance to all tested antibiotics except colistin. Notably, there has been a substantial prevalence of carbapenem-resistant P. aeruginosa, A. baumannii, and K. pneumoniae in the past five years. This alarming situation calls for greater attention and precaution with prescribed antibiotics to limit the generation and spread of new multidrug-resistant bacteria and improve therapeutic management.

Methicillin Resistant Staphylococcus Aureus Colonization among HIV Patients

Introduction: Methicillin-resistant S. aureus is known to have a significant negative impact on both immunocompetent and immunocompromised individuals (HIV patients). Aim: This study evaluated the antibiotic susceptibility profile of MRSA staphylococcus aureus isolated from HIV patients attending Barau Dikko Teaching Hospital, Kaduna. Methods: Using sterile wet swabs, within the period of 3 months (January– March 2020), a total of 180 samples were collected from the skin, ear, and nasal cavities of 60 HIV patients who gave their consent to be part of the survey, and S. aureus was isolated. Isolation, bacterial characterization, and antimicrobial susceptibility tests were carried out using the methods described by Chesbrough and Kirby-Bauer, respectively. Results: The bacterial isolation rate was 76.7% (138/180) in the samples collected, with 56.5% (78) been Gram positive. The incidences of S. aureus and MRSA were 12.8% and 8.6%, respectively. From the sample sources, the distribution of S. aureus was more in the nostrils, followed by the skin and ear swabs. Resistance was observed against imipenem (86.9%), vancomycin (65.3%), tetracycline (65.3%), and erythromycin (60.9%), while susceptible to ciprofloxacin (60.9%), streptomycin (43.5%), and gentamycin (52.2%). A high percentage (91.3%) of S. aureus were multidrug-resistant and had MARI &gt; 0.2. Conclusion: This study established that high-resistant S. aureus with a possible MRSA gene could be responsible for frequent staphylococcus-associated infections and resistance to treatment among HIV patients in Kaduna, Nigeria. Doi: 10.28991/SciMedJ-2023-05-03-03 Full Text: PDF

Identification of Bacterial Isolates and Their Antimicrobial Susceptibility Pattern from Wound/Pus Sample in a Tertiary Care Hospital, Gwalior, India

Objective The goal of this investigation was to look at the frequency and dispersal of bacteria isolated from pus/wound, as well as their susceptibility patterns. Materials and Methods A study was conducted on 175 patients who provided pus and/or wound discharge samples in different wards (outpatient department or inpatient department). MacConkey agar and blood agar plates were immediately inoculated with samples and incubated at 37°C for 24 hours. The Gram stain and biochemical tests were used to identify all isolates after incubation. Kirby–Bauer's disc diffusion method was used to perform sensitivity tests on Mueller–Hinton agar plates. Results This study covered 175 patients, with a bacterial isolation rate of 102 (58.28%). Males outnumbered females in the samples (M:F = 1.8:1), with a median age of 45 years as majority were in the age group of 40 to 60 years which was 41 (40.20%). Total 90.1% samples showed monomicrobial infection, whereas 9.8% showed polymicrobial infection, and total 112 bacterial strains were isolated. Conclusion Escherichia coli was the most prevalent isolate in present investigation, followed by Pseudomonas aeruginosa. Chloramphenicol is the only antibiotic which is effective for both gram-negative bacilli and gram-positive cocci. This report's susceptibility statistic may be worth considering for developing empiric treatment regimens for pyogenic infections.

Analysis of Cumulative Antibiotic Sensitivity Testing Data (Antibiogram) of Anwer Khan Modern Medical College Hospital

Background: Monitoring of antimicrobial resistance at local level is a very crucial aspect for clinical decision making, infection control interventions and antimicrobial-resistance containment strategies in this era of rising superbugs. The hospital antibiogram constructed by standardized method is a summary of antimicrobial susceptibilities of local bacterial isolates, with periodic review.&#x0D; Methods: This is a prospective observational study conducted in Microbiology Laboratory of Anwer Khan Modern Medical College Hospital (AKMMCH) over a period of three months from January to March 2021. All the samples which were received in the microbiology laboratory for aerobic bacterial culture and antibiotic sensitivity testing were considered in this study. The bacterial isolates from diagnostic clinical samples were subjected to culture in appropriate media for isolation of pathogens by standard methods and antibiotic sensitivity test (AST) was performed according to CLSI guidelines by modified Kirby Bauer disk diffusion techniques.&#x0D; Results: A total of 2917 samples were analysed in the microbiology department of AKMMCH for a period of three months of which 513(17.59%) were culture positive.Among the cultured samples of urine, respiratory sample, blood and pus, wound swabs, the rate of bacterial isolation was 266 (51.85%) ,161 (31.38%), 31 (6.04%) and 33 (6.4%) respectively. Most of the clinical isolates were Gram-negative bacilli404 (78.75%). The predominant isolate was Escherichia coli 186(36.26%) followed by Pseudomonas spp 102 (19.88%), Klebsiellaspp 79 (15.4%) and S. aureus 66 (12.87%). Antibiotic sensitivity in case of Gram-negative bacteria ranges from 30%-61% to amoxicillin-clavulanic acid, 18%-94% to third generation cephalosporin, 47%-75% to aminoglycosides, 27% -70% to ciprofloxacin, 26-70% to cotrimoxazole, 33-73% to nitrofurantoin, 27-69% to piperacillin- tazobactam and 100% to colistin. However, 53% of Escherichia coli and 58% of Klebsiella spp. were resistant to 3rd generation cephalosporins due to extended-spectrum beta-lactamase (ESBL) production. The carbapenem resistance in Escherichia coli was found 12%, Klebsiella spp 26%, Pseudomonas spp 29% and highest in Acinetobacter 46%. No superbug was detected in this study period.&#x0D; Conclusions: Antimicrobial susceptibility of various pathogen for different antibiotic is variable. Prompt antimicrobial therapy in an infection makes a lot of difference between recovery and death and most of the time prevents long term disability. Hence, antibiotic policy is one of the mandatory requirements and making an antibiogram is the first step before framing antibiotic policy.&#x0D; AKMMC J 2021; 12(2): 70-75

Characterization of Escherichia coli and other bacteria isolated from condemned broilers at a Danish abattoir.

Meat inspection is important to ensure food safety and protect public health. Visual inspection of slaughtered carcasses for pathological changes should be supported by bacteriological analysis to determine whether the entire carcass or parts of it should be condemned. The aim of this study was to determine the bacterial species present in different sample types from condemned broiler carcasses. Furthermore, we investigated the genetic characteristics, zoonotic potential, and relatedness of Escherichia coli, the predominant bacterial species isolated from the carcasses. A total of 400 broiler carcasses condemned because of cellulitis (100), scratches (100), hepatitis (100), and healthy control carcasses (100) were selected. Samples of meat, pathological lesion, and bone marrow of each carcass were obtained for microbial analysis. From the analyzed samples, 469 bacterial isolates were recovered with E. coli accounting for 45.8%, followed by Aeromonas spp. (27.9%), in particular A. veronii. The highest rate of bacterial isolation was observed in carcasses condemned with cellulitis, whereas carcasses with hepatitis had the lowest rate of bacterial isolation. Forty-four E. coli isolates originating from different sample types were selected for whole genome sequencing. A clonal relationship was shown between E. coli from different sample types of the same carcass condemned with cellulitis and scratches. A major clade of E. coli was found in carcasses condemned with cellulitis with isolates containing mdf(A), tet(A), and bla TEM-1B genes that confer resistance to macrolides, tetracycline, and ampicillin, respectively. E. coli in this clade all belonged to ST117 and clustered with E. coli isolates previously collected from dead chickens and carcasses condemned due to cellulitis in Denmark, Finland, and the United Kingdom. Bacterial evaluation results of carcasses condemned with cellulitis, scratches (moderate to severe skin lesion), and acute hepatitis confirmed the need for total condemnation of carcasses with these pathological findings. A similar evaluation should be done for carcasses affected with chronic hepatitis, and minor scratches lesions.

A Culture-antibiogram of Sterile Body Fluids in a Tertiary Care Hospital at Central Delhi in Emergency Settings

Infection of sterile body fluids could be life-threatening. Monitoring of prevailing infectious agents and their resistance pattern through antibiogram helps in appropriate selection of antibiotics and strengthens antibiotic stewardship. The aim of this study is to isolate infective bacteria from sterile body fluids and to determine antibiotic resistant pattern of these isolates. This retrospective observational study was conducted through January 2018–December 2018 in a tertiary care hospital at central Delhi. Sterile body fluids were processed as per the standard laboratory procedures. Antibiotic susceptibility pattern was determined by Kirby Bauer’s disk diffusion method and interpreted as per Clinical and Laboratory Standards Institute guidelines. A total of 3,703 fluid samples were studied. Out of them 49.9% were ascitic fluid, 39.4% were pleural fluid, and 10.7% were others such as pericardial fluid, synovial fluid, bile, peritoneal dialysis fluid, and bronchoalveolar lavage fluid. Bacterial isolation rate was 12.93%. Predominant organisms were Escherichia coli (31%), Acinetobacter spp. (20%), Klebsiella spp. (16%), Staphylococcus aureus (11%), and Enterococcus spp. (10%). Isolation of vancomycin resistant enterococcus was 9.5% and Methicillin resistant S. aureus was 15.6%. Gram-negative isolates were 100% sensitive to colistin, followed by imipenem and gentamicin. Increased resistance shown toward third generation cephalosporins, amoxicillin + clavulinic acid, and piperacillin + tazobactum. Klebsiella spp. was the most resistant isolate, while Enterococcus spp. was the most resistant among gram positive isolates. Changing antimicrobial pattern poses challenge in treating infective agents. This culture antibiogram helps in appropriate selection of antibiotics in our setting and eventually decrease antibiotic resistant and patient’s morbidity and mortality.

An Evaluation of a Simplified Impression Membrane Sampling Method for the Diagnosis of Microbial Keratitis.

The purpose of this study was to compare bacterial isolation rate using a corneal impression membrane (CIM) and a sharp instrument for obtaining corneal samples from patients with suspected microbial keratitis (MK). Data was retrospectively collected for all patients that had corneal samples taken for presumed MK between May 2014 and May 2020. Prior to May 2017 samples were collected by scraping the edges of the ulcer with a blade. From May 2017, samples were collected by placing a CIM (Millicell cell culture insert) against the ulcer. All corneal samples were processed using the same conventional diagnostic culture method. A total of 3099 corneal samples were included, of which 1214 (39.2%) were corneal scrapes and 1885 (60.9%) CIMs. Microorganisms were isolated from 235 (19.4%) and 1229 (65.2%) cases using a corneal scrape and CIM, respectively (p < 0.001). Of routinely described pathogenic microorganisms, there were significant increases in the isolations of S. aureus (2.4% to 11.3%) and Serratia (0.5% to 1.7%) using the CIM and no significant changes in the isolations of S. pneumoniae and P. aeruginosa. No significant differences were seen between the isolation rates of fungi or Acanthamoeba species. There was a significant increase in the isolation rates of other Streptococcal species (0.7% to 6.9%) and CNS species, specifically, S. epidermidis (2.1% to 26.2%), S. capitis (0.4% to 2.6%) and S. warneri (0.3% to 1.6%) using the CIM. The simplified CIM sampling method is an effective method for collecting corneal samples from patients with presumed MK in clinical practice.

Vibrio Species in an Urban Tropical Estuary: Antimicrobial Susceptibility, Interaction with Environmental Parameters, and Possible Public Health Outcomes.

The genus Vibrio comprises pathogens ubiquitous to marine environments. This study evaluated the cultivable Vibrio community in the Guanabara Bay (GB), a recreational, yet heavily polluted estuary in Rio de Janeiro, Brazil. Over one year, 66 water samples from three locations along a pollution gradient were investigated. Isolates were identified by MALDI-TOF mass spectrometry, revealing 20 Vibrio species, including several potential pathogens. Antimicrobial susceptibility testing confirmed resistance to aminoglycosides, beta-lactams (including carbapenems and third-generation cephalosporins), fluoroquinolones, sulfonamides, and tetracyclines. Four strains were producers of extended-spectrum beta-lactamases (ESBL), all of which carried beta-lactam and heavy metal resistance genes. The toxR gene was detected in all V. parahaemolyticus strains, although none carried the tdh or trh genes. Higher bacterial isolation rates occurred in months marked by higher water temperatures, lower salinities, and lower phosphorus and nitrogen concentrations. The presence of non-susceptible Vibrio spp. was related to indicators of eutrophication and sewage inflow. DNA fingerprinting analyses revealed that V. harveyi and V. parahaemolyticus strains non-susceptible to antimicrobials might persist in these waters throughout the year. Our findings indicate the presence of antimicrobial-resistant and potentially pathogenic Vibrio spp. in a recreational environment, raising concerns about the possible risks of human exposure to these waters.

Bacteriological profile and antibiotic susceptibility patterns of wound infections in a tertiary care hospital in South India

Infections caused due to injuries are due to microbial proliferation at the wound site following skin damage. Initial testing of micro-organisms in terms of culturing and sensitivity leads to appropriate antibiotic selection and prevents escalation of antimicrobial resistance.To evaluate the bacteriological profile and antibiotic susceptibility patterns of wound infections in this single-centered study.The study included 160 patients suspected to have wound infection. Pus or tissue samples collected from patients were subjected to microbiological processing including Gram staining, culture and antibiotic susceptibility testing. Their demographic data and wound related factors (duration, nature, type) were recorded. The isolated organisms were evaluated for β-lactamase production using Extended spectrum β-lactamase (ESBL) test, Modified Hodge test for Carbapenemase and AmpC β-lactamase enzyme detection tests. Most participants were 41-60 years old (45.63%). The majority had surgical site infections (SSI, 91.25%), early infected (91.1%) and clean (67.12%) wounds. The bacterial isolation rate was 80% and 45.27% (n=67) were Gram positive isolates, out of which 47 (70.14%) were multidrug resistant. was identified as the predominant organism (n=40), where 33 among 40 were methicillin sensitive, followed by (n=30, 23.43%). Amongst the Gram negative isolates (n=81, 54.73%), 60 (74.07%) were multidrug resistant with majority being susceptible to imipenem, meropenem and amikacin. The most common pathogen associated with wound infection was Methicillin sensitive with SSI being the most common type of wound infection.

Study of Normal Flora in the Pharynx of Healthy Children.

To improve our current understanding of normal flora in children, we investigated bacterial isolates from the pharynx and nasopharynx of 173 and 233 healthy children, respectively. The bacterial isolation rates were compared among three age groups: infants (<1 year), toddlers (1-5 years), and school-aged children (6-15 years). Gram-positive cocci were the predominant bacteria in the pharynx (Streptococcus mitis/oralis, 87.3%; Streptococcus salivarius, 54.3%; Rothia mucilaginosa, 41.6%; Staphylococcus aureus, 39.3%). Among infants, S. salivarius and Neisseria subflava, which are related to the development of teeth, were significantly lower than in the other age groups (P <0.0001, S. salivarius; P <0.01, N. subflava). With the exception of Corynebacterium pseudodiphtheriticum (44.2%, gram-positive rods), gram-negative rods largely predominated the nasopharynx (Moraxella catarrhalis, 32.1%; Moraxella nonliquefaciens, 28.3%). Among toddlers, M. catarrhalis and Streptococcus pneumoniae, which are the most common pathogens in acute otitis media, were significantly higher than in the infant group (P <0.05). Among the bacterial species implicated in pediatric respiratory infections, Streptococcus pyogenes was isolated in 3.5% of the pharyngeal samples. S. pneumoniae and Haemophilus influenzae were isolated in 22.3% and 17.2% of the nasopharyngeal samples, respectively. In conclusion, the normal flora of the respiratory tract differs not only by the sampling site but also by the age group.

Identification of contaminants as members of the Bacillus pumilus group and analysis of contamination sources in the cultivation of Pleurotus geesteranus mushrooms

Oyster mushroom (Pleurotus geesteranus Singer) is grown widely in China withut problems, but occasionally severe bacterial contamination occurred in cultivation bags of Pleurotus geesteranus during high summer temperatures in some companies in the Chunan county of Zhejiang province in 2018, belonging to the so-called Bacillus pumilus group by morphological characteristics, 16S rRNA, GyrB and aroE genes sequencing, fatty acid analysis and MALDI analysis. The inoculation tests confirmed that Bacillus pumilus strains were contaminants causing mycelial disappearance of P. geesteranus. The dual culture tests demonstrated that several strains of B. pumilus were able to inhibit mycelial growth of P. geesteranus. In order to find the sources of contamination the, process of mushroom cultivation was investigated. A 41.0% contamination rate occurred in cultivation bags with sponge plugs, as opposed to a very low contamination rate (<4%) in cultivation bags with cotton plugs. It was also shown that a 13.0% bacterial isolation rate was obtained from autoclaved sponge pieces, as opposed to 2.0% or 0.0% from cotton pieces, respectively. Fifteen strains isolated all were identified by MALDI-Biotyper as Bacillus spp., belonging to four species (Bacillus circulans, B. pumilus, B.cereus and B. halosaccharovorans). Dual culture tests showed that B. circulans, B. cereus and B. halosaccharovorans strains had not inhibitory effect on mycelial growth of P. geesteranus. This study furthermore shows that sponge plugs containing B. pumilus contaminants were the contamination source in cultivation bags of P. geesteranus.

Reduction in Bacterial Isolation Rate with Improved Compliance for the Use of Alcohol-based Hand Rub

Reduction in Bacterial Isolation Rate with Improved Compliance for the Use of Alcohol-based Hand Rub

Ocular findings in a group of healthy captive leopard geckos.

Leopard Geckos (Eublepharis macularius) are popular pets and can be affected by a range of ocular disorders. Our objective was to report ocular findings in a group of healthy captive leopard geckos and to establish reference ranges for commonly performed ocular diagnostic tests. Twenty-six healthy male geckos aged 1year old (n=4) and >2years old (n=22). All animals underwent ophthalmic examination, corneal esthesiometry, modified Schirmer tear test (mSTT), rebound tonometry, conjunctival bacterial aerobic and fungal culture, and measurement of ocular dimensions. Student's t test was used to compare values of corneal esthesiometry, tonometry and mSTT between groups. Multiple correlations were assessed by Pearson correlation coefficient. All animals had a normal ocular examination. Tear production as measured with a mSTT (mean±SD) technique was 3.1±1.3mm/min and tonometry values (mean±SD) were 8.2±1.7mmHg. Corneal touch threshold (median, range) was 4.4cm, 2.5-5.0. Younger animals had a significantly increased corneal sensitivity compared to older animals (P=.0383). Results of culture showed no growth for fungal organism in any animals. Conjunctival bacterial isolation rates were low, with only 7/26 samples positive for nine bacterial species. Leopard geckos are amenable to ophthalmic examination and ocular diagnostic database testing with minimal manual restraint.

Comparison of bronchoalveolar lavage fluid bacteriology and cytology in calves classified based on combined clinical scoring and lung ultrasonography

Respiratory tract infections are the leading cause of antimicrobial use in calves. Combining clinical examination and lung ultrasonography allows on-farm classification of calves as healthy or suffering from an upper respiratory tract infection (URTI), subclinical or clinical pneumonia. This might help to improve targeted antimicrobial therapy, restricting treatment to pneumonic cases. However, to what extent these diagnostic categories coincide with expected bacteriological and cytological bronchoalveolar lavage fluid (BALf) characteristics is currently unknown. The objective of this study was therefore to compare BALf bacteriology and cytology between healthy calves and calves with URTI, subclinical and clinical pneumonia. The hypothesis was that calves with subclinical and clinical pneumonia would have higher quantitative bacterial counts, bacterial isolation rates and neutrophil counts than URTIs or healthy animals. A cross-sectional study was performed on 305 indoor group-housed dairy and beef calves, from 62 farms. Calves were classified by combining clinical examination and lung ultrasonography. Clinical respiratory disease was defined using the Wisconsin score card and the Healthy Criterion (HC). The HC classified calves as clinically ill if at least one clinical sign was present. Ultrasonographic lung consolidation with a depth of ≥1 cm was considered indicative for pneumonia. Cytology and bacteriology were performed on BALf sampled by non-endoscopic bronchoalveolar lavage. Calves with clinical pneumonia were further subdivided based on culture result and presence of neutrophils phagocytosing bacteria. Combined lung ultrasonography and clinical examination (HC) classified 25.9 % (79/305) of the calves as healthy, 33.1 % (101/305) as URTI, 10.2 % (31/305) as subclinical and 30.8 % (94/305) as clinical pneumonia. Bacterial isolation rates and quantitative BALf culture results did not differ between groups. Calves with clinical pneumonia and neutrophil phagocytosis showed a significantly higher BALf neutrophil percentage compared to healthy calves (59.0 % vs. 37.7 % in healthy calves, P =.03). Inversely, lymphocyte percentage was lower in these calves (1.8 % vs. 5.3 % in healthy calves, P = .003). Classification of calves using lung ultrasonography and clinical scoring did not correspond with BALf bacteriology and cytology findings, as extrapolated from human and companion animal medicine. Under the current housing conditions of this study high rates of non-infectious airway inflammation or airway colonization by opportunistic pathogens, rather than infection might explain this. Isolation of respiratory pathogens from calves with various signs of respiratory disease or ultrasonographic lesions should be interpreted carefully. Of all cytological features, phagocytosis by neutrophils in BALf might be a useful criterion supporting the diagnosis of bacterial respiratory tract infection.

Optimization of Culturomics Strategy in Human Fecal Samples

Most bacteria in the human gut are difficult to culture, and culturomics has been designed to overcome this issue. Culturomics makes it possible to obtain living bacteria for further experiments, unlike metagenomics. However, culturomics is work-intensive, which prevents its wide application. In this study, we performed a 30-day continuous enrichment in blood culture bottles and cultured bacterial isolates from pre-cultures removed at different time points. We compared the bacteria isolated from the enriched culture with or without adding fresh medium after each pre-culture was removed. We also compared “experienced” colony picking (i.e., picking two to three colonies for each recognized colony type) and picking all the colonies from each plate. In total, from five fecal samples, 106 species were isolated, including three novel species and six that have not previously been isolated from the human body. Adding fresh medium to the culture increased the rate of bacterial species isolation by 22% compared with the non-supplemented culture. Picking all colonies increased the rate of bacterial isolation by only 8.5% compared with experienced colony picking. After optimization through statistical analysis and simulation, sampling aerobic and anaerobic enrichment cultures at six and seven time-points, respectively, is likely to isolate >90% of bacterial species, reducing the workload by 40%. In conclusion, an extended enrichment step ensures isolation of different bacterial species at different time-points, while adding the same quantity of fresh medium after sampling, the experienced picking and the optimized time-points favor the chance of isolating more bacterial species with less work.

Pathogens in the Meibomian gland and conjunctival sac: microbiome of normal subjects and patients with Meibomian gland dysfunction.

ObjectiveTo explore the composition of the ocular microbiome in normal subjects and patients with Meibomian gland dysfunction (MGD).Subjects and methodsSeventy subjects (140 eyes) were enrolled in our study. Signs of dry eye were evaluated and bacterial species in the conjunctival sac (CS) and Meibomian gland (MG) secretions were then identified by 16S rRNA gene sequencing. Additionally, 17 subjects (34 eyes) were further evaluated to determine differences in the microbiomes in the surface and deep layers of MG using a segmental secretion analysis.ResultsThe positive bacterial isolation rate was markedly higher in MG secretions than in the CS. The bacterial composition of the control and mild group was simple, whereas the composition of bacteria was more complex as the severity of MGD increased. The positive bacterial isolation rate and number of bacterial types were significantly higher in the severe MGD group than those in the control, mild and moderate MGD groups. Corynebacterium macginleyi was only detected in the severe MGD group, with an isolation rate of up to 26.3%. Furthermore, a new grading system for bacterial severity of MGD was proposed and the severity of MGD appeared to be positively correlated with a higher grade of bacterial severity. The segmental secretion analysis showed severe MGD had a significantly higher incidence of bacterial discordance rate.ConclusionThe severity of MGD was positively correlated with a higher isolation rate, a greater number of bacterial species, and a higher grade of bacterial severity, which implied that MGD might be correlated with bacterial changes. This study provided some basis for the indications of antibiotic in clinical practice.

Bacterial Flora of the Conjunctiva One Year after Dacryocystorhinostomy.

PURPOSE:The purpose of this study was to evaluate the changes of conjunctival bacterial flora 1 year after successful dacryocystorhinostomy (DCR).METHODS:Seventy-two consecutive adult patients with successful DCR were enrolled in this study. We obtained conjunctival cultures from the operated eyes, fellow eyes, and nasal mucosa of the operated side 1 year after the operation. After the period of incubation, further evaluation was performed using standard laboratory techniques.RESULTS:In the conventional media, positive bacterial growth was detected in 48 (66.7%) of the 72 operated eyes and in 31 of the 72 normal fellow eyes (43.1%). Nasal specimens were positive for bacterial growth in 65 (90.3%) patients. Isolation rate was significantly different between the operated and the fellow (nonoperated) eyes (P = 0.0074). Colony count, type, and frequencies of bacterial isolation from the operated eyes were similar to nonoperated eyes.CONCLUSION:One year after DCR, conjunctival bacterial isolation rate increased compared with the normal fellow eyes. Remote DCR may be considered as a local risk factor for developing postoperative endophthalmitis.

A suitable blood agar containing human blood especially for the use in laboratories of developing countries

In developed countries, blood agar containing defibrinated sheep or horse blood is a standard tool for the isolation of bacteria from clinical samples. Several issues prevent blood agar containing animal blood from being used in many developing countries. However, the use of easily available human blood for blood agar is discouraged because of the common tenet that human blood in nutrient media results in poor bacterial isolation rates and hardly visible hemolysis or no hemolysis at all. We have developed a reconfigured and easily applicable composition for blood agar containing human blood and tested its usability with respect to hemolysis visibility and its characteristics in antibiograms with Streptococcus spp. Hemolysis tests were conducted with clinical strains of Staphylococcus aureus, Streptococcus dysgalactiae, and Streptococcus mitis. In a second test series, clinical strains of Streptococcus dysgalactiae, Streptococcus agalactiae, and Streptococcus mitis were tested with Mueller-Hinton agars containing defibrinated wether blood as well as with Mueller-Hinton agars containing citrated human blood to compare the results of antibiotic susceptibility testing. The reconfigured blood agars containing 2.5% citrated human blood showed almost identical reactions to the standard blood agars used in the developed world. For the first time, blood agars containing 2.5% citrated human blood were shown to be an acceptable alternative for the isolation of the above-mentioned bacteria as well as for use in antibiotic susceptibility testing.