BACKGROUND: We characterized the antimicrobial resistance (AMR) profiles of Neisseria gonorrhoeae (NG) isolated from symptomatic men at a sexually transmitted infection clinic in Kisumu, Kenya.
METHODS: Two urethral swabs were obtained from symptomatic men between 2020 and 2022, one for Gram\'s stain and the other inoculated directly onto modified Thayer-Martin media containing 1% VCNT and 1% IsoVitaleX enrichment. Culture results were confirmed by colony morphology, Gram\'s stain and oxidase test. Duplicate isolates were shipped to Uniformed Services University for confirmation and characterization. Susceptibility to eight drugs was assessed by E-test. Agar dilution confirmed resistance to ceftriaxone, cefixime, and azithromycin. Susceptibility, intermediate resistance (IR), and resistance (R) were determined according to published criteria.
RESULTS: Of 154 enrolled participants, 112 were culture-positive for NG. Agar dilution results in 110 (98.2%) showed the following: azithromycin-R (1.8%), and 4.5% R or IR to ceftriaxone or cefixime: ceftriaxone-R (0.9%), ceftriaxone-IR (2.7%), and cefixime-IR (2.7%). By E-test, most isolates were IR or R to tetracycline (97.2%), penicillin (90.9%), and ciprofloxacin (95.4%).
CONCLUSIONS: We detected NG with resistance to azithromycin and ceftriaxone, indicating a growing threat to the current Kenyan dual syndromic treatment of urethritis with cephalosporin plus macrolides. Ongoing AMR surveillance is essential for effective drug choices.

UNASSIGNED: Determining oxacillin susceptibility using reference methods and automated systems is crucial for treating invasive infections caused by Staphylococcus aureus. This study compares the oxacillin susceptibility results from the two automated systems with agar dilution and correlates them with genotypes of invasive S. aureus.
UNASSIGNED: Non-duplicate S. aureus invasive isolates were collected over an 11-year period. The oxacillin susceptibility was determined with Phoenix 100 (Jan 2011 to Aug 2018) or Vitek 2 (Sep 2018 to Dec 2021), and susceptibility for oxacillin and cefoxitin was determined with agar dilution. Methicillin-resistant S. aureus (MRSA) was confirmed with mecA existence, and the genotype was determined using SCCmec. The association between genotype and antibiotic susceptibility using two automated systems and agar dilution was evaluated.
UNASSIGNED: A total of 842 invasive S. aureus, including 443 mecA+ MRSA and 399 mecA- MSSA, were collected. The susceptibility rates of oxacillin determined by two automated systems and agar dilution were 68.8% (76.8% for Phoenix 100 and 57.6% for Vitek 2) and 54.0%, respectively. When compared with the oxacillin susceptibility using agar dilution, the categorical agreement for Phoenix 100 and Vitek 2 were 0.46% and 0.88%, respectively (p < 0.001). One hundred and forty-three isolates were misinterpreted as oxacillin-susceptible S. aureus (OSSA) using automated systems while comparing with agar dilution, among which molecularly community-associated MRSA (CA-MRSA) outnumbered healthcare-associated MRSA (HA-MRSA) (99 vs 34, p < 0.001). There were 70 mecA+ OSSA (OS-MRSA) using agar dilution, among which 42 harbored SCCmec types were predominantly categorized as CA-MRSA (38, p < 0.001).
UNASSIGNED: The categorical agreement of Vitek 2 in determining oxacillin susceptibility and predicting mecA existence is comparable with agar dilution, whereas Phoenix 100 is not. Most of those ORSA determined by agar dilution but misinterpreted as OSSA by automated systems and OS-MRSA are categorized as CA-MRSA.

Antimicrobial susceptibility tests (AST) conducted in vitro offer a range of methods to assess the antimicrobial resistance (AMR) of microorganisms. Escherichia coli, a widely distributed bacterium, is closely linked to the issue of AMR. In this way, the present study aimed to assess the agreement among different in vitro AST methods, including disk diffusion in agar, broth dilution, and agar dilution method. A total of 100 E. coli isolates were analyzed for their resistance levels against six antibiotics: amoxicillin, ceftiofur, ciprofloxacin, chloramphenicol, tetracycline, and sulfamethoxazole + trimethoprim, using the aforementioned AST methods. Standard breakpoint values were employed to classify isolates as resistant, intermediate, or susceptible, and comparisons among the AST methods were conducted by McNemar\'s test (P < .05). The obtained data demonstrated equivalence among the AST methods, highlighting the reliability of these standardized classical methodologies. This standardization aids in preventing the inappropriate use of antimicrobials and the dissemination of antimicrobial-resistant microorganisms.

BACKGROUND: Human infections due to Eubacterium are rare and knowledge of the condition is limited. This study aimed to describe clinical characteristics and outcome in patients with Eubacterium bacteremia.
METHODS: Episodes of Eubacterium bacteremia were identified through the clinical microbiology laboratory in Lund, Sweden. Medical records were retrospectively reviewed. Blood isolates of Eubacterium were collected and antibiotic susceptibility testing was performed with agar dilution.
RESULTS: Seventeen patients with Eubacterium bacteremia were identified of whom six had monomicrobial bacteremia. The incidence was 1.7 cases of Eubacterium bacteremia per million inhabitants and year. The median age was 67 years (interquartile range 63-79 years), and six patients had some form of malignancy. Most of the patients an abdominal focus of infection and the 30-day mortality was low (n = 1).
CONCLUSIONS: Invasive infections with Eubacterium have a low incidence. The condition has a low mortality and an abdominal focus of infection, and malignancy, is common.

UNASSIGNED: Asymptomatic bacteriuria (ASB) is a common finding during pregnancy. Effective antibiotic treatment could reduce its adverse effects on both mother and fetus. However, emerging antimicrobial resistance limits the treatment options. Fosfomycin might be a promising drug in this regard, as its resistance is still low. The aim of the study was to determine the antimicrobial susceptibility pattern of fosfomycin in isolates causing ASB by disc diffusion and agar dilution (in selected isolates), determine minimum inhibitory contribution (MIC) by agar dilution in isolates resistant by disc diffusion and detect the genes responsible for fosfomycin resistance.
UNASSIGNED: This was a 2-year study carried in the Department of Microbiology, Jawaharlal Nehru Medical College and Hospital (JNMCH), Aligarh Muslim University (AMU), Aligarh. A total of 10 252 urine samples from asymptomatic pregnant females (18-45 years) attending the antenatal care (ANC) outpatient department (OPD) were submitted. Identification of pathogen and antimicrobial susceptibility testing (AST) was carried out as per standard methods of CLSI. There was phenotypic detection of methicillin-resistant Staphylococcus aureus (MRSA) and other Staphylococcus species (MRSS), high-level aminoglycoside resistance (HLAR), vancomycin resistant Enterococci (VRE) and S. aureus (VRSA), extended spectrum β-lactamase (ESBL) and carbapenem-resistant Enterobacterales (CRE). All the fosfomycin-resistant isolates (by disk diffusion) were tested by agar dilution. Conventional PCR was performed for murA, fosA, uhpT and glpT genes on all resistant isolates.
UNASSIGNED: In this study, the prevalence of ASB among pregnant females was 1173(11.4 %), in which Escherichia coli 495(42 %) was the predominant organism. The overall sensitivity of fosfomycin among Gram-positive cocci (GPC) and Gram-negative bacilli (GNB) was 99 % and 97.6 %, respectively. MRSA and MRSS accounted for 50 (66.6 %) and 71 (76 %), respectively. The highest rates of MIC >2048 µg ml-1 were shown by most isolates (mainly E. coli ) on agar dilution. PCR studies revealed four E. coli strains possessed both murA (also present in one K. pneumoniae strain) and glpT genes. While only one isolate ( E. faecalis ) was positive for fosA gene. But none of the strain possessed the uhpT gene.
UNASSIGNED: According to this study, murA and glpT genes were more frequent than fosA. We cannot comment on the prevalence and regional distribution of fosfomycin-resistant genes based on this preliminary study. Therefore, more Indian studies should be carried out to create awareness about the presence of genes in a particular area.

Agar dilution is the gold standard method for phenotypic antimicrobial susceptibility testing (AST) for Neisseria gonorrhoeae. However, this method is laborious and requires expertise, so laboratories that perform N. gonorrhoeae AST may choose alternative methods such as disk diffusion and gradient diffusion. In this study, we retrospectively compare the performance of gradient diffusion to agar dilution for 2,394 unique N. gonorrhoeae isolates identified in Alberta from 2017 to 2020 against azithromycin, cefixime, ceftriaxone, ciprofloxacin, penicillin, and tetracycline. Genome sequencing was utilized to resolve discrepancies between AST methods, detect antimicrobial resistance markers, and identify trends between error rates and sequence types (STs) of isolates. Over 90% of N. gonorrhoeae isolates were susceptible to azithromycin, cefixime, and ceftriaxone, whereas decreased susceptibility was observed for ciprofloxacin, penicillin, and tetracycline. Categorical (CA) and essential agreement (EA) was poorest between the two methods for penicillin (CA: 86.02%; EA: 77.69%) and tetracycline (CA: 47.22%; EA: 55.96%); however, the low CA was primarily attributed to minor errors. Antimicrobial agents with errors outside of acceptable limits included azithromycin (very major error: 18.42%; major error: 7.73%) and tetracycline (very major error: 6.17%). Genome sequencing on a subset of isolates resolved 30.3% of the azithromycin major errors and confirmed the azithromycin or tetracycline very major errors. Significant associations between certain STs and error types for azithromycin and tetracycline were also identified. Overall, gradient diffusion compared well to agar dilution for cefixime, ceftriaxone, and ciprofloxacin, and genome sequencing was identified as a useful tool to arbitrate discrepant susceptibility testing results between gradient diffusion and agar dilution for N. gonorrhoeae.

Aims and Objectives  Mupirocin is a widely used topical antibiotic for the treatment of skin and soft tissue infections. This has resulted in resistance leading to treatment failure. Hence, the present study aimed to determine the prevalence of mupirocin resistance among staphylococcal isolates obtained from the skin and soft tissue infections. Also, comparison of disc diffusion and agar dilution method in detecting mupirocin resistance was done. Materials and Methods  This cross-sectional study was conducted in the Department of Microbiology of a tertiary health care center in Karnataka from January to December, 2018. Clinical samples such as wound swabs, tissues, and pus were included in the study. All staphylococcal isolates were screened for mupirocin resistance using 5 µg and 200 µg discs for low-level (MuL) and high-level mupirocin resistance (MuH), respectively. Minimum inhibitory concentration (MIC) was determined using the agar dilution method. Results  Out of 100 staphylococcal isolates, 68 were Staphylococcus aureus and 32 were CoNS. MuH was detected in 11 isolates. MuH was more common in CoNS (10/11) compared with S. aureus (1/11). MuL was not found in the study. Discussion  In our study, 10 out of 11 mupirocin-resistant isolates were methicillin resistant, which is statistically significant ( p  < 0.05). The correlation between results of disc diffusion and MIC were appropriate in this study. Conclusion  Judicial prescription of mupirocin after knowing the susceptibility report should become the standard practice. Screening for mupirocin resistance can be done by disc diffusion in resource-limited settings.

BACKGROUND: Fosfomycin is an old bactericidal drug that has gained increasing interest in the last decade for its potential use in multi-drug resistant gram-negative infections. However, evidence on fosfomycin susceptibility testing reports a poor correlation between commercial methods vs. reference agar dilution (AD) for Enterobacterales (EB). The study aimed at assessing the performance of two automated systems for the determination of fosfomycin susceptibility in EB clinical isolates.
METHODS: Fosfomycin susceptibility testing results of two collections of 100 non-duplicate clinical EB strains obtained using two different platforms (BD Phoenix and MicroScan WalkAway Plus) were compared with those obtained by AD. Categorical agreement (CA), major error (ME) and very major error (VME) rates were calculated.
RESULTS: BD Phoenix exhibited a 6.9% rate of false-resistant results and achieved a CA of 69%, whereas MicroScan WalkAway Plus achieved 3.7% of false-resistant results and 72% of CA. Both automated systems showed poor detection of resistant isolates, with 49.1% and 56.2% of false-susceptible results for BD Phoenix and Microscan WalkAway Plus, respectively.
CONCLUSIONS: Overall, agar dilution remains the most suitable method for routine laboratory antimicrobial susceptibility testing of fosfomycin on Enterobacterales strains, given the poor performance of automated systems. The application of both automated systems, in the clinical laboratories reporting of fosfomycin, should be reviewed in light of the accuracy results falling below the acceptable threshold.

BACKGROUND: In this study, efficacy and consistency of disc diffusion (DD) and agar dilution (AD) methods in determining Helicobacter pylori susceptibility to antibiotics were evaluated using Brucella blood agar (BBA) in both methods and tetrazolium egg yolk agar (TEYA) in AD. METHODS: Twenty H. pylori isolates were tested for susceptibility to nine antibiotics; metronidazole (MTZ), clarithromycin (CLR), amoxicillin (AMX), tetracycline (TET), ofloxacin (OFX), levofloxacin (LVX), ciprofloxacin (CIP), furazolidone (FRZ), and rifampin (RIF). Antibiotics solutions were impregnated into blank paper disks on BBA in the DD method or added to BBA (ADB) or TEYA (ADT) media in the AD method. Suspensions of H. pylori isolates were surface or spot inoculated on solid media. Plates were incubated in CO2 incubator at 37°C for 5-7 days. RESULTS: The highest rate of susceptibility to MTZ (65%) was determined by DD method compared with AD method (ADB: 40%, ADT: 30%). Both methods showed similar CLR (85%) and AMX (100%) susceptibility rates. Susceptibility to remaining antibiotics, determined by DD and ADB/ADT media were in respective order as 95%, 75% / 75% for TET, 100%, 95% / 85% for FRZ, 85%, 85% / 75% for OFX, 90%, 95% / 85% for LVX, 90%, 85% / 85% for CIP, and 100%, 85% / 75% for RIF. CONCLUSION: DD and AD methods showed consistency in determining 161 (89.4%) susceptibility and resistance and inconsistency in determining 19 (10.6%) susceptibility and resistance (P < 0.05). DD is recommended as a cheap and easy method with the efficacy and precision comparable to the AD method in determining H. pylori susceptibility to antibiotics.

UNASSIGNED: Urinary tract infection is one of the most common bacterial infections causing high morbidity and mortality. The alarming rise of multidrug-resistant uropathogens worldwide forced the clinician to rethink the old drugs like Fosfomycin for its therapeutic management. Our objective was to compare agar dilution, disc diffusion and E-test method for antimicrobial susceptibility testing of Fosfomycin against different drug-resistant uropathogens.
UNASSIGNED: Consecutive 181 uropathogens were tested for Fosfomycin susceptibility using agar dilution, disc diffusion and E-test. Results were interpreted using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. Whole genome sequencing analysis was done on the 4 XDR/PDR Fosfomycin resistant Klebsiella pneumoniae isolates.
UNASSIGNED: Escherichia coli was found as the most common (62.4%) uropathogen followed by Klebsiella pneumoniae (21%). Considering agar dilution as the gold standard, 6.1% of isolates were resistant to Fosfomycin. Following CLSI breakpoints, the susceptibility of Escherichia coli, Klebsiella pneumoniae, other Enterobacterales and Pseudomonas aeruginosa were 92.9%, 92.1%, 100%, 100%; whereas using EUCAST breakpoints the susceptibility rates were 85.7%, 86.9%, 92.9%, and 100%, respectively. The essential agreement, categorical agreement, major error, and very major error for E-test/disc diffusion for all the organisms were 91.2%/Not Applicable, 95%/93.9%, 1.8%/4.7%, 9.1%/9.1%, respectively. Whole-genome sequencing showed mutation UhpT gene as well as the presence of plasmid-mediated fosA5 or fosA6 genes conferring Fosfomycin resistance.
UNASSIGNED: This result supports very low resistance of Enterobacterales against Fosfomycin; hence should be considered a valuable option to treat multidrug-resistant uropathogens. Disc diffusion was observed to be a convenient method for Fosfomycin susceptibility testing compared to agar dilution.