Detection of Decreased Fluoroquinolone Susceptibility in Salmonellas and Validation of Nalidixic Acid Screening Test

We evaluated 1,010 Salmonella isolates classified as fluoroquinolone susceptible according to the National Committee for Clinical Laboratory Standards guidelines for susceptibility to nalidixic acid and three fluoroquinolones. These isolates were divided into two distinct subpopulations, with the great majority (n = 960) being fully ciprofloxacin susceptible and a minority (n = 50) exhibiting reduced ciprofloxacin susceptibility (MICs ranging between 0.125 and 0.5 μg/ml). The less ciprofloxacin-susceptible isolates were uniformly resistant to nalidixic acid, while only 12 (1.3%) of the fully susceptible isolates were nalidixic acid resistant. A similar association was observed between resistance to nalidixic acid and decreased susceptibility to ofloxacin or norfloxacin. A mutation of the gyrA gene could be demonstrated in all isolates for which the ciprofloxacin MICs were ≥0.125 μg/ml and in 94% of the nalidixic acid-resistant isolates but in none of the nalidixic acid-susceptible isolates analyzed. Identification of nalidixic acid resistance by the disk diffusion method provided a sensitivity of 100% and a specificity of 87.3% as tools to screen for isolates for which the MICs of ciprofloxacin were ≥0.125 μg/ml. We regard it as important that microbiology laboratories endeavor to recognize these less susceptibleSalmonella strains, in order to reveal their clinical importance and to survey their epidemic spread.

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Antibiotic susceptibility of campylobacter isolates from sewage and poultry abattoir drain water

Epidemiology and Infection ◽

10.1017/s0950268800058635 ◽

1995 ◽

Vol 115 (3) ◽

pp. 475-483 ◽

Cited By ~ 12

Author(s):

P. M. F. J. Koenraad ◽

W. F. Jacobs-Reitsma ◽

T. Van Der Laan ◽

R. R. Beumer ◽

F. M. Rombouts

Keyword(s):

Nalidixic Acid ◽

Clinical Laboratory ◽

Quinolone Resistance ◽

Diffusion Method ◽

National Committee ◽

Meat Processing ◽

Disk Diffusion Method ◽

Sources Of Infection ◽

Sewage Purification

SummaryIn this study, thein vitrosusceptibility of 209 campylobacter strains to the quinolones nalidixic acid, flumequine, ciprofloxacin, enrofloxacin, and to ampicillin, tetracycline and erythromycin was tested by the disk diffusion method. The strains were isolated from poultry abattoir effluent (DWA) and two sewage purification plants (SPA and SPB). Sewage purification plant SPA received mixed sewage, including that from a poultry abattoir, whereas SPB did not receive sewage from any meat-processing industry. The quinolone resistance of the DWA isolates ranged from 28% for enrofloxacin to 50% for nalidixic acid. The strains isolated from the sewage purification plants were more susceptible to the quinolones with a range of 11–18% quinolone resistance for SPB isolates to 17–33% quinolone resistance for SPA isolates. The susceptibility criteria as recommended by National Committee Clinical Laboratory Standards (USA) cannot readily be employed for campylobacter isolates. This investigation shows that the resistance of campylobacter bacteria is highest in the plant receiving sewage from a poultry slaughterhouse. Monitoring of antibiotic resistance of aquaticCampylobacterspp. is important, as surface waters are recognized as possible sources of infection.

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Antimicrobial resistance Salmonella isolates recovered from food products of animal origin in the Russian Federation

Access Microbiology ◽

10.1099/acmi.ac2020.po0025 ◽

2020 ◽

Vol 2 (7A) ◽

Author(s):

Galina Skitovich ◽

Kseniya Serova ◽

Yevgenia Korchagina ◽

Natalya Shadrova

Keyword(s):

Antibiotic Resistance ◽

Nalidixic Acid ◽

Acid Resistance ◽

Food Products ◽

Poultry Meat ◽

Animal Origin ◽

Diffusion Method ◽

Disk Diffusion Method ◽

The Russian Federation ◽

Nalidixic Acid Resistance

The study was aimed at Salmonella isolation from samples of animal food products submitted for testing from various regions of the Central part of the RF and serotyping of the recovered isolates and their testing for antibiotic resistance. A total of 2,342 tests were performed and 87 (3.7%) Salmonella isolates were recovered. Most of them (54 isolates) were recovered from poultry meat and poultry meat preparation samples submitted for testing. Besides, 25 isolates were recovered from pork and pork preparation samples, 7 isolates – from beef samples, 1 isolate – from hard cheese samples. Serotyping of 64 Salmonella isolates showed that the majority of the isolates (57.8%) belonged to О7 group. Also, Salmonella isolates belonging to О9 (21.9%), О8 (9.4%), О4,5 (6.2%) and О10 (4.7%) were detected in food products. S. Enteritidis, (23.3%), and S. infantis (18.7%), were predominant based on the number of detections. Also, the following serovars were identified: S. typhimurium, S. nigeria, S. montevideo, S. derby, S. meleagridis, S. virchov, S. oranienburg. Tests of 87 Salmonella isolates for their antibiotic resistance with disk diffusion method revealed that they were highly resistant to nalidixic acid (70.1%), tetracycline (49.4%), trimethoprim/sulfamethoxazol (40.2%). Moreover, nalidixic acid-resistance was common for all identified isolates. Seventeen isolates (19.5%) demonstrated multiple antibiotic resistance and two isolates were found to be resistant to ≥7 antibiotics. All recovered isolates were susceptible to gentamicin, amikacin, meropenem and imipenem. Obtained results indicate the necessity of Salmonella antibiotic resistance monitoring to gain understanding of Salmonellas’ antibiotic resistance emergence and trends.

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The frequency of resistance to antibiotics of most frequently isolated bacteria from blood cultures during the period 1997-2002

Vojnosanitetski pregled ◽

10.2298/vsp0404391m ◽

2004 ◽

Vol 61 (4) ◽

pp. 391-397

Author(s):

Veljko Mirovic ◽

Branka Tomanovic ◽

Sonja Konstantinovic

Keyword(s):

Clinical Laboratory ◽

Blood Cultures ◽

Diffusion Method ◽

National Committee ◽

Disk Diffusion Method ◽

Beta Lactamases ◽

Resistance To Antibiotics ◽

Extended Spectrum Beta Lactamases ◽

High Level

The aim of this study was to determine the frequency of resistance to antibiotics of the most frequently isolated bacteria from blood cultures of hospitalized patients during the period 1997-2002. The resistance to antibiotics was determined by disk diffusion method according to National Committee for Clinical Laboratory Standards procedures. The majority of staphylococci isolates were resistant to methicillin, and the proportion of methicillin-resistant Staphylococcus aureus was stable (76.8-81.6%), during the follow-up period. None of the staphylococci isolates were resistant to vancomycin, but there was a very high incidence of high-level resistance of enterococci to aminoglycosides (47.2-72.2%). In 1998, only one strain among enterococci was resistant to vancomycin (Enterococcus faecium, VanA fenotype). Enterococcus spp isolates expressed variable frequency of resistance to ampicillin (15-40.1%) during the follow-up period. Among Enterobacteriaceae there were no isolates resistant to imipenem, but dramatic increase of the resistance to ceftriaxone was found from 35.9% in 1997 to 95.9% in 2002 (p<0.001). Extended spectrum beta-lactamases production was found in all the species of enterobacteria isolates. Resistance to imipenem was observed in Acinetobacter spp isolates in 2002 for the first time. Pseudomonas spp isolates expressed high and very variable resistance to all antibiotics tested during the follow-up period.

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Comparision of Antibiotic Susceptility of Levofloxacin with Other Commonly Tested Antibiotics Against Salmonella Enterica Serovar (Typhi And Paratyphi A)

Nepal Journal of Medical Sciences ◽

10.3126/njms.v3i1.10344 ◽

2014 ◽

Vol 3 (1) ◽

pp. 19-21

Author(s):

A Chhetri ◽

A Manandhar ◽

Y Shah ◽

RC Simkhada ◽

R Paudyal ◽

...

Keyword(s):

Nalidixic Acid ◽

Salmonella Enterica ◽

Antibiotic Susceptibility ◽

Enteric Fever ◽

Clinical Laboratory ◽

Acid Resistance ◽

Fluoroquinolone Resistance ◽

Diffusion Method ◽

Salmonella Enterica Serovar Typhi ◽

Antibiotic Susceptibility Test

Background: Increasing antibiotic resistance of bacteria is a global problem. Fluoroquinolones are recommended as first line therapy for children and adults infected with Salmonella enterica serovar Typhi and Paratyphi A. The purpose of this study was to compare the antibiotic susceptibility pattern of different classes of antibiotics with levofloxacin from blood samples of suspected enteric fever patients visiting Birhospital, Kathmandu. Methods: Antibiotic susceptibility test was performed by Kirby-Bauerdisc diffusion method as per Clinical Laboratory Standards Institute guideline. Results: Among 50 isolates of Salmonella enterica, 39 (78%) were S.Typhi and 11 (22%) were S. Paratyphi A. All the isolates were tested against antibiotics, and all isolates were found sensitive to chloramphenicol and ceftriaxone whereas 3 isolates of S. Typhi were resistant to ciprofloxacin and 1 was resistant to levofloxacin. Fluoroquinolone resistant S. ParatyphiA was not observed. Among the 10 (20%) multi drug resistant isolates, only 1 isolate was resistant to levofloxacin which was S. Typhi. Both S.Typhi (96.7%) and S. Paratyphi A (89.4%) were resistant to Nalidixic acid. Conclusion: High level of nalidixic acid resistance and even some fluoroquinolone resistance showed that the treatment of the enteric fever cannot be relied on the fluoroquinolones. Nepal Journal of Medical Sciences | Volume 03 | Number 01 | January-June 2014 | Page 19-21 DOI: http://dx.doi.org/10.3126/njms.v3i1.10344

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REVIEW OF FIFTY CULTURE PROVEN SALMONELLA CASES

Indian Journal of Medical Sciences ◽

10.18203/issn.0019-5359.indianjmedsci20163534 ◽

2016 ◽

Vol 68 (1) ◽

pp. 67

Author(s):

Shalini Duggal ◽

Priyanka Banerjee ◽

Tulsi D. Chugh

Keyword(s):

Acid Resistance ◽

Retrospective Chart Review ◽

Automated System ◽

Total Leukocyte Count ◽

Diffusion Method ◽

Disk Diffusion Method ◽

Reactive Protein ◽

Antibacterial Susceptibility ◽

Culture Positive ◽

Nalidixic Acid Resistance

BACKGROUND: Enteric fever has huge global burden. Surrogate markers may have a role in early diagnosis. AIM: Unselected retrospective analysis of 50 culture positive Salmonella enterica cases for epidemiology, laboratory markers, antibacterial susceptibility, therapy, and outcome was done. This was a retrospective chart review of electronic medical records for 50 patients with Salmonella in blood cultures for in our hospital during May 2009-April 2010. MATERIALS AND METHODS: Blood culture was by automated Bactec™ system and antimicrobial susceptibility test was performed by disk diffusion method or automated system Phoenix 100™. Sensitivity of Widal, S. typhi IgM, C-reactive protein (CRP), total leukocyte count, erythrocyte sedimentation rate (ESR), differential eosinophil and lymphocyte counts, and liver enzymes, was determined for these cases. RESULTS: Salmonella cases were seen in all ages from 8 months to 59 years; serotype Typhi was the most common (72%). Sensitivity of S. typhi IgM immunochromatographic test was 78.9%, of Widal was 88.8%, and that of CRP, serum aspartate transaminase (AST), and serum alanine transaminase (ALT) ranged from 81.8 to 89.4%. Eosinophil count of zero and ESR were found to be 78.2% and 85.7% sensitive. Nalidixic acid resistance was seen in 96% cases and ciprofloxacin resistance/intermediate sensitivity in 26% cases. Resistance was not seen with ceftriaxone, while ampicillin, chloramphenicol, and co-trimoxazole (ACCo) resistance was 4%. Seven cases relapsed mostly due to improper treatment associated with choice/dose/duration of antibiotics. CONCLUSIONS: Surrogate laboratory markers can be utilized pending culture results. Though antibiotics and vaccines against Salmonella, and good sanitation facilities are available, it causes morbidity in all sections, gender, and ages of society. Strategies of prevention have not been very successful; therefore, early detection and effective treatment can prevent its complications and relapses.

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Department of Microbiology, Bangladesh Agricultural University, Mymensingh

Bangladesh Journal of Medical Microbiology ◽

10.3329/bjmm.v2i2.28839 ◽

2016 ◽

Vol 2 (2) ◽

pp. 3-6

Author(s):

Nahida Akther Zahan ◽

Md. Akram Hossain ◽

AKM Shamsuzzaman ◽

AKM Musa ◽

Md. Chand Mahamud ◽

...

Keyword(s):

Clinical Laboratory ◽

Methicillin Resistance ◽

Meca Gene ◽

Toxin Production ◽

Latex Agglutination ◽

Diffusion Method ◽

National Committee ◽

Dilution Method ◽

Agar Dilution Method ◽

Disk Diffusion Method

The study was done to detect different exotoxins among the strains of Staphylococcus aureus isolated in the department of Microbiology, Mymensingh Medical College in collaboration with the Department of Medicine under the Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh between the periods from July, 2006 to June, 2007. A total of 40 S. aureus isolates investigated in this study were identified by standard microbiological techniques. Antimicrobial susceptibility of the isolates to Oxacillin was carried out by disk diffusion method as per recommendation of the National Committee for Clinical Laboratory Standards. Any isolate showing resistance to Oxacillin was tested again by agar dilution method to determine minimum inhibitory concentration (MIC) of Methicillin. All strains were also tested for mecA gene by Polymerase Chain Reaction (PCR) for confirmation of Methicillin resistance. Enterotoxin (A-D) and Toxic Shock Syndrome Toxin-1 (TSST-1) were detected by Reverse Passive Latex Agglutination (RPLA) test. Out of 40 S. aureus isolates, 7 (17.5%) Methicillin Resistant S. aureus (MRSA), 1 (2.5%) Methicillin Sensitive S. aureus (MSSA) produced Staphylococcal Enterotoxin A (SE-A) and 1 MRSA isolate was positive for TSST-1. In case of combined toxin production among the S. aureus isolates, 2 (5%) MSSA were found to produce SE-A and SE-B, 2 (5%) MSSA produced SE-C and SE-D, and 1 (2.5%) MRSA, 1 (2.5%) MSSA produced SE-C and TSST-1.Bangladesh J Med Microbiol 2008; 02 (02): 3-6

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Use of an Oxacillin Disk Screening Test for Detection of Penicillin- and Ceftriaxone-Resistant Pneumococci

Journal of Clinical Microbiology ◽

10.1128/jcm.37.4.1178-1181.1999 ◽

1999 ◽

Vol 37 (4) ◽

pp. 1178-1181 ◽

Cited By ~ 5

Author(s):

Louise P. Jetté ◽

Christian Sinave

Keyword(s):

Antimicrobial Agents ◽

Clinical Laboratory ◽

Disk Diffusion ◽

Diffusion Method ◽

National Committee ◽

Zone Of Inhibition ◽

Diffusion Test ◽

Disk Diffusion Method ◽

Disk Diffusion Test ◽

Intermediate Resistance

In a context of worldwide emergence of resistance amongStreptococcus pneumoniae strains, early detection of strains with decreased susceptibility to β-lactam antibiotics is important for clinicians. If the 1-μg oxacillin disk diffusion test is used as described by the National Committee for Clinical Laboratory Standards, no interpretation is available for strains showing zone sizes of ≤19 mm, and there is presently no disk diffusion test available for screening cephalosporin resistance. The zones obtained by the diffusion method by using the 1-μg oxacillin disk were compared with penicillin MICs for 1,116 clinical strains and with ceftriaxone MICs for 695 of these strains. Among the 342 strains with growth up to the 1-μg oxacillin disk margin, none were susceptible (MIC, ≤0.06 μg/ml), 62 had intermediate resistance (MIC, 0.12 to 1.0 μg/ml), and 280 were resistant (MIC, ≥2.0 μg/ml) to penicillin. For ceftriaxone, among 98 strains with no zone of inhibition in response to oxacillin, 68 had intermediate resistance (MIC, 1.0 μg/ml), and 22 were resistant (MIC, ≥2.0 μg/ml). To optimize the use of the disk diffusion method, we propose that the absence of a zone of inhibition around the 1-μg oxacillin disk be regarded as an indicator of nonsusceptibility to penicillin and ceftriaxone and recommend that such strains be reported as nonsusceptible to these antimicrobial agents, pending the results of a MIC quantitation method.

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Nalidixic Acid Susceptibility Test for Screening Salmonella Isolates of Reduced Susceptibility/Higher Minimum Inhibitory Concentration to Ciprofloxacin

Nepal Journal of Science and Technology ◽

10.3126/njst.v15i2.12122 ◽

2015 ◽

Vol 15 (2) ◽

pp. 97-104 ◽

Cited By ~ 1

Author(s):

P. Agrawal ◽

R. Tuladhar ◽

N. Dahal

Keyword(s):

Nalidixic Acid ◽

Enteric Fever ◽

Acid Resistance ◽

Susceptibility Test ◽

Diffusion Method ◽

Dilution Method ◽

Agar Dilution Method ◽

Disc Diffusion ◽

Antibiotic Susceptibility Test ◽

Nalidixic Acid Resistance

Enteric fever is the major diagnosis among febrile patients in Nepal with yearly increase in nalidixic acid resistance and reduced ciprofloxacin susceptibility among Salmonella isolates. This study was carried out to evaluate the validity of nalidixic acid resistance as an indicator of reduced susceptibility of Salmonella isolates to ciprofloxacin. In this study, 999 blood specimens collected from suspected enteric fever patients visiting B&B Hospital were processed by standard microbiological techniques. Isolates were identified by biochemical tests and serotyping. Antibiotic susceptibility test was performed by Kirby Bauer disc diffusion method and CLSI recommended interpretive criteria. MIC of ciprofloxacin was determined by agar dilution method. Isolation rate of Salmonella species was 6.21%. Among 62 Salmonella isolates, 51 were S. typhi, 10 were S. paratyphi A and one isolate was S. paratyphi B. Only one isolate of S. typhi was multi-drug resistant. Resistance to ceftriaxone, cefixime and azithromycin was nil. On disc diffusion test, 55 isolates were resistant to nalidixic acid. Fifty-seven isolates were found to have increased (>0.125mg/ml) MIC of ciprofloxacin with the clinical and laboratory standards institute breakpoints. Nalidixic acid resistance showed a predictive value of 100% for ciprofloxacin resistance. Screening with nalidixic acid disc had a sensitivity of 100% and a specificity of 71.43% for the determination of decreased ciprofloxacin susceptibility. Before using ciprofloxacin for the treatment of enteric fever, appropriate identification of Salmonella isolates with reduced ciprofloxacin susceptibility is essential to limit the possible treatment failure and further development of highly resistant strains.DOI: http://dx.doi.org/njst.v15i2.12122Nepal Journal of Science and Technology Vol. 15, No.2 (2014) 97-104

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Incidence of Quinolone Resistance Over the Period 1986 to 1998 in Veterinary Salmonella Isolates from Germany

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.9.2278 ◽

1999 ◽

Vol 43 (9) ◽

pp. 2278-2282 ◽

Cited By ~ 50

Author(s):

Burkhard Malorny ◽

Andreas Schroeter ◽

Reiner Helmuth

Keyword(s):

Nalidixic Acid ◽

Phage Type ◽

Acid Resistance ◽

Inhibition Zone ◽

Fluoroquinolone Resistance ◽

Diffusion Method ◽

High Incidence ◽

Paratyphi B ◽

Resistant Strains ◽

Nalidixic Acid Resistance

ABSTRACT A total of 24,591 nonhuman salmonella strains isolated in Germany between 1986 and 1998 were examined for their resistance to nalidixic acid by an agar diffusion method. The rate of resistance (inhibition zone, ≤13 mm) ranged from 0.2% in 1986 to a peak of 14.8% in 1990. Between 1991 and 1998 the MICs for nalidixic acid-resistant strains ranged from more than 256 μg/ml for nalidixic acid to between 0.25 and 128 μg/ml for enrofloxacin. In the early 1990s a particularly high incidence of fluoroquinolone resistance (49.5%) was seen among isolates of Salmonella enterica serotype Typhimurium (Salmonella Typhimurium) definitive phage type 204c that mainly originated from cattle. Among isolates from poultry an increase in the incidence of nalidixic acid resistance to a peak of 14.4% was observed in 1994. This peak was due to the presence of specific resistant serotypes, mainly serotypes Hadar, Saintpaul, Paratyphi B (d-tartrate positive; formerly serotype Java) and Newport. Such strains exhibited a decreased susceptibility to enrofloxacin (MIC, 1 μg/ml). Among isolates from pigs the peak incidence of resistance was reached in 1993, with 7.5% of isolates resistant to nalidixic acid and enrofloxacin. The study demonstrates an increase in the incidence of strains that are resistant to nalidixic acid and that have decreased susceptibility to enrofloxacin after the licensing of enrofloxacin. In addition, the number of other serotypes that exhibited nalidixic acid resistance or reduced enrofloxacin susceptibility increased among the total number of isolates investigated between 1992 and 1998.

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Comparison of antimicrobial susceptibilities of Corynebacterium species by broth microdilution and disk diffusion methods.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.40.4.930 ◽

1996 ◽

Vol 40 (4) ◽

pp. 930-933 ◽

Cited By ~ 29

Author(s):

K Weiss ◽

M Laverdière ◽

R Rivest

Keyword(s):

Clinical Laboratory ◽

High Rate ◽

Disk Diffusion ◽

Diffusion Method ◽

National Committee ◽

Broth Microdilution ◽

Disk Diffusion Method ◽

Corynebacterium Species ◽

Broth Microdilution Method

Corynebacterium species are increasingly being implicated in foreign-body infections and in immunocompromised-host infections. However, there are no specific recommendations on the method or the criteria to use in order to determine the in vitro activities of the antibiotics commonly used to treat Corynebacterium infections. The first aim of our study was to compare the susceptibilities of various species of Corynebacterium to vancomycin, erythromycin, and penicillin by using a broth microdilution method and a disk diffusion method. Second, the activity of penicillin against our isolates was assessed by using the interpretative criteria recommended by the National Committee for Clinical Laboratory Standards for the determination of the susceptibility of streptococci and Listeria monocytogenes to penicillin. Overall, 100% of the isolates were susceptible to vancomycin, while considerable variations in the activities of erythromycin and penicillin were noted for the different species tested, including the non-Corynebacterium jeikeium species. A good correlation in the susceptibilities of vancomycin and erythromycin between the disk diffusion and the microdilution methods was observed. However, a 5% rate of major or very major errors was detected with the Listeria criteria, while a high rate of minor errors (18%) was noted when the streptococcus criteria were used. Our findings indicate considerable variations in the activities of erythromycin and penicillin against the various species of Corynebacterium. Because of the absence of definite recommendations, important discrepancies were observed between the methods and the interpretations of the penicillin activity.

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