Corynebacterium striatum: An emerging nosocomial pathogen in a case of laryngeal carcinoma.

Corynebacterium striatum is an emerging nosocomial pathogen associated with wound infections, pneumonia and meningitis. It is also a multidrug-resistant pathogen causing high morbidity. This is a report of an unusual case of wound infection in a patient with laryngeal carcinoma. Accurate diagnosis of the infection and prompt management helped in a favourable outcome for the patient. This case highlights the role of C. striatum as an important nosocomial pathogen in immunocompromised patients.

Evaluation of a modified double-disc synergy test for detection of extended spectrum beta-lactamases in AMPC beta-lactamase-producing proteus mirabilis.

The detection of extended-spectrum beta-lactamases (ESBLs) in gram-negative bacteria that produce AmpC beta-lactamases is problematic. In the present study, the performance of modified double-disc synergy test (MDDST) that employs a combination of cefepime and piperacillin-tazobactam for the detection of Proteus mirabilis producing extended spectrum and AmpC beta-lactamases was evaluated and compared with double-disc synergy test (DDST) and NCCLS phenotypic disc confirmatory test (NCCLS-PDCT). A total of 90 clinical isolates of P. mirabilis , which met the CLSI (Clinical and Laboratory Standards Institute) screening criteria that these had broth microdilution (BMD) MIC of > or =2 mg/mL for at least one extended spectrum cephalosporin [ceftazidime (CAZ), cefotaxime (CTX) and cefpodoxime], were selected for the study. MDDST detected ESBLs in 40/90 of the isolates, whereas DDST detected ESBLs in only 25 isolates. NCCLS-PDCT could detect ESBLs in 39 isolates using CAZ and CAZ + clavulanic acid (CLA) combination, whereas CTX and CTX + CLA combination could detect only 37 isolates as ESBL positive. As many as 34/40 ESBL positive isolates were confirmed to be AmpC beta-lactamase positive by the modified three-dimensional test (MTDT). MDDST and NCCLS-PDCT could detect ESBLs in all the 34 AmpC positive isolates, whereas DDST could detect ESBLs in only 19 isolates. The study demonstrated that MDDST is superior to DDST and as sensitive as NCCLS-PDCT. However, MDDST seems to have enhanced potential for the detection of ESBLs in AmpC beta-lactamase-producing P. mirabilis .

Evaluation of methods for AmpC beta-lactamase in gram negative clinical isolates from tertiary care hospitals.

The purpose of this study was to simultaneously screen for Extended-spectrum beta-lactamases (ESBL) and AmpC beta-lactamases in gram negative clinical isolates from four tertiary care hospitals and further to compare two detection methods three-dimensional extraction method and AmpC disk test for AmpC beta-lactamases. A total of 272 isolates were screened for ESBL and AmpC beta-lactamase by modified double disk approximation method (MDDM). Synergy observed between disks of ceftazidime/cefotaxime and clavulanate were considered as ESBL producer. Isolates showing reduced susceptibility to either of the test drugs (ceftazidime or cefotaxime) and cefoxitin were considered as presumptive AmpC producers and further confirmed by three-dimensional extraction method and AmpC disk test. A total of 173 (64%) of the isolates were found to be ESBL positive and 61 (23%) showed resistant to cefoxitin. ESBL was detected in 80 (62%) isolates of E. coli and 71 (73%) of Klebsiella spp. The occurrence of AmpC beta-lactamases was found to be 8% (22) of the total isolates and the two detection methods for AmpC beta-lactamase showed concordant results. Screening for ESBL and AmpC can be simultaneously done by MDDM method and confirmation for AmpC beta-lactamase should be carried out routinely in tertiary care hospitals by AmpC disk test, as it is a simple and rapid procedure.