Treatment failure in a typhoid patient infected with nalidixic acid resistant S. enterica serovar Typhi with reduced susceptibility to Ciprofloxacin: a case report from Cameroon

BACKGROUND: Fluoroquinolones or third generation cephalosporins are the drugs of choice for the treatment of typhoid fever. Treatment failure with fluoroquinolones has been reported in Asia and Europe. We report a case of ciprofloxacin treatment failure in typhoid fever in Cameroon. CASE PRESENTATION: A 29-year-old female patient with suspected typhoid fever from Kumba, Cameroon, yielded growth of Salmonella enterica serovar Typhi in blood culture. The isolate was resistant to nalidixic acid but sensitive to ciprofloxacin by disc diffusion test. However, the patient did not respond to treatment with ciprofloxacin, although the isolate was apparently susceptible to ciprofloxacin. CONCLUSION: Treatment failure with ciprofloxacin in our case indicates the presence of nalidixic acid resistant S. enterica serovar Typhi (NARST) with reduced susceptibility to ciprofloxacin in Cameroon (Central Africa)

In vitro activity of tigecycline against methicillin-resistant Staphylococcus aureus, including livestock-associated strains

The in vitro activity of tigecycline was determined using a well-defined collection of methicillin-resistant Staphylococcus aureus (MRSA) isolates (n = 202), including 33 livestock-associated strains. Susceptibility testing was performed using the Etest system. Among the 202 MRSA strains, three (1.5%) had a minimum inhibitory concentration (MIC) value for tigecycline greater than 0.5 mg/l, which are considered to be resistant. When these strains were tested using Iso-Sensitest medium, the MICs were substantially lower and no resistance was found. This discrepancy warrants further investigations into the preferred test conditions for tigecycline. In conclusion, tigecycline showed good activity against MRSA strains in vitro

Development of a rapid, reliable and quantitative method – “SPOTi” for testing antifungal efficacy

A reference method for the antimicrobial susceptibility testing of common fungal pathogens such as dermatophytes, is currently lacking. In this study, we report the successful adaptation of solid agar-based spot culture growth inhibition assay (SPOTi) for dermatophytes, currently being used as a gold-standard in the anti-tubercular drug discovery field. The fungal-SPOTi assay correlated with the disc-diffusion method, and is validated using mycelial plugs. We propose the fungal-SPOTi as a high-throughput alternative to the disc-diffusion and broth micro-dilution anti-fungal assays to screen novel anti-fungals

Molecular Analysis of Isoleucyl-tRNA Synthetase Mutations in Clinical Isolates of Methicillin-Resistant Staphylococcus aureus with Low-Level Mupirocin Resistance

Emergence and spread of low-level mupirocin resistance in staphylococci have been increasingly reported in recent years. The aim of this study was to characterize missense mutations within the chromosomal isoleucyl-tRNA synthetase gene (ileS) among clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) with low-level mupirocin resistance. A total of 20 isolates of MRSA with low-level mupirocin resistance (minimal inhibitory concentration, 16-64 µg/mL) were collected from 79 patients in intensive care units for six months. The isolates were analyzed for isoleucyl-tRNA synthetase (IleS) mutations that might affect the binding of mupirocin to the three-dimensional structure of the S. aureus IleS enzyme. All isolates with low-level mupirocin resistance contained the known V588F mutation affecting the Rossman fold, and some of them additionally had previously unidentified mutations such as P187F, K226T, F227L, Q612H, or V767D. Interestingly, Q612H was a novel mutation that was involved in stabilizing the conformation of the catalytic loop containing the KMSKS motif. In conclusion, this study confirms that molecular heterogeneity in ileS gene is common among clinical MRSA isolates with low-level mupirocin resistance, and further study on clinical mutants is needed to understand the structural basis of low-level mupirocin resistance

Chronic Pulmonary Disease Due to Mycobacterium monacense Infection: The First Case from Iran

We herein report a case in which the recently characterized species Mycobacterium monacense was isolated from the sputum of an Iranian patient. This case represents the first isolation of M. monacense from Iran. The isolate was identified by conventional and molecular techniques. Our findings show that M. monacense infection is not restricted to developed countries

Fungaemia due to Cryptococcus laurentii and a review of non- neoformans cryptococcaemia

Cryptococcus laurentii is one of several non- neoformans cryptococci that have rarely been associated with human infection. The spectrum of clinical infection due to non- neoformans species ranges from skin lesions to fungaemia. Most cases of non- neoformans fungaemia have been noso-comially acquired and have been associated with indwelling intravascular catheters and neutropenia. Limited data on in vitro susceptibilities of non- neoformans cryptococci show these species to be more resistant to fluconazole and flucytosine than most Cr. neoformans. Two such cases are presented here. Zusammenfassung . Cryptococcus laurentii ist eine von mehreren nicht- neofomans-Cryptococcus -Arten, die selten mit Krankheiten am Menschen in Zusammenhang gebracht werden. Das Spektrum durch Nicht- neoformans -Arten bedingter klinischer Infektionen reicht von HautlÄsionen bis zur FungÄmie. Die Mehrzahl der FÄlle von nicht- neoformans -FungÄmie waren nosokomial bedingt und mit intravasalen Dauerkathetern und Neutropenie assoziiert. Die wenigen Daten Über In-vitro-SuszeptibilitÄt von Non- neoformans -Arten fÜr Fluconazol und Flucytosin sprechen dafÜr, daß diese Arten resistenter als die meisten Cr. neoformans-StÄmme sind. Zwei solcher FÄlle werden vorgestellt.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72398/1/j.1439-0507.1998.tb00338.x.pd

Colistin-sparing regimens against Klebsiella pneumoniae carbapenemase-producing K. pneumoniae isolates: Combination of tigecycline or doxycycline and gentamicin or amikacin

AbstractBackground/PurposeIn vitro studies of the combination of an aminoglycoside with tigecycline or doxycycline against Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae isolates are rarely published. The goal of this study was to evaluate the antibacterial activity of the combination regimens.MethodsThirteen genetically different KPC-producing K. pneumoniae isolates were randomly selected. Drug concentrations of amikacin, gentamicin, tigecycline, and doxycycline were adjusted to 1-, 1/2-, and 1/4-fold of respective minimum inhibitory concentrations (MICs). Each drug alone or the combinations of amikacin or gentamicin with tigecycline or doxycycline were tested by combination studies.ResultsTreatment with the 1× MIC concentration in combinations of amikacin or gentamicin and tigecycline or doxycycline for 24 hours resulted in bactericidal activity of 84–100% in the isolates. Treatment with 1/2× MIC combinations resulted in synergism of 69–100% in the isolates. Notably, doxycycline plus gentamicin or amikacin was synergistic for all tested isolates. However, bactericidal or synergistic effect was barely evident following 1/4× MIC combinations. There was no antagonism in any of the combination regimens.ConclusionEnhanced activity was noted following treatment with doxycycline combined with gentamicin or amikacin against KPC-producing K. pneumoniae isolates, warranting further in vitro and animal investigations before clinical application

Secular trends of antimicrobial resistance of blood isolates in a newly founded Greek hospital

BACKGROUND: Antimicrobial resistance is one of the most challenging issues in modern medicine. METHODS: We evaluated the secular trends of the relative frequency of blood isolates and of the pattern of their in vitro antimicrobial susceptibility in our hospital during the last four and a half years. RESULTS: Overall, the data regarding the relative frequency of blood isolates in our newly founded hospital do not differ significantly from those of hospitals that are functioning for a much longer period of time. A noteworthy emerging problem is the increasing antimicrobial resistance of Gram-negative bacteria, mainly Acinetobacter baumannii and Klebsiella pneumoniae to various classes of antibiotics. Acinetobacter baumannii isolates showed an increase of resistance to amikacin (p = 0.019), ciprofloxacin (p = 0.001), imipenem (p < 0.001), and piperacillin/tazobactam (p = 0.01) between the first and second period of the study. CONCLUSION: An alarming increase of the antimicrobial resistance of Acinetobacter baumannii isolates has been noted during our study