In vitro production of biofilm in a flow cell system in a strain of Pseudomonas aeruginosa and Staphylococcus aureus and determination of efficiency of ciprofloxacin against them.

Background: Microorganisms develop biofilm on various medical devices. The process is particularly relevant in public health since biofilm associated organisms are much more resistant to antibiotics and have a potential to cause infections in patients with indwelling medical devices. Materials and Methods: To determine the efficiency of an antibiotic against the biofilm it is inappropriate to use traditional technique of determining Minimum Inhibitory Concentration (MIC) on the free floating laboratory phenotype. Thus we have induced formation of biofilm in two strains (Pseudomonas aeruginosa and Staphylococcus aureus, which showed heavy growth of biofilm in screening by Tube method) in a flow cell system and determined their antibiotic susceptibility against ciprofloxacin by agar dilution method in the range (0.25 mg/ml to 8 mg/ml). The MIC value of ciprofloxacin for the biofilm produced organism was compared with its free form and a standard strain as control on the same plates. Observations: Both the biofilm produced strains showed a higher resistance (MIC > 8 mg/ml) than its free form, which were 2 μg/ml for Pseudomonas aeruginosa and 4 mg/ml for Staphylococcus aureus. Thus biofilm can pose a threat in the patient treatment.

Ceftriaxone resistant Shigella Flexneri, an emerging problem.

Shigellosis is a disease of public health importance in developing countries. It may cause self-limited diarrhea to severe dysentery. Emergence of multi drug resistant (MDR) strains is a growing concern globally. Ceftriaxone and ciprofloxacin are the drugs of choice for MDR cases. Here, we report a case of MDR Shigella flexneri from an immunocompromised patient. The strain was resistant to ceftriaxone [minimum inhibitory concentration (MIC) ≥ 64 μg/ml], limiting the treatment option. Simultaneously, the strain was also found to be resistant to ciprofloxacin (MIC ≥ 4 μg/ml). However, it was susceptible to ceftazidime (MIC 4 μg/ml). This is the first case of ceftriaxone resistant Shigella spp. reported from our hospital.

Comparação entre três métodos de coloração a frio no diagnóstico primário de tuberculose: um estudo piloto / Comparison among three cold staining methods in the primary diagnosis of tuberculosis: a pilot study

OBJETIVO: Em países em desenvolvimento, a baciloscopia é a principal ferramenta para a identificação de casos de tuberculose pulmonar. O objetivo do presente estudo foi avaliar a eficácia diagnóstica do método de coloração de Gabbett (MCG) e de um método modificado de coloração a frio (MMC), ambos em duas etapas, em comparação com a do método de coloração fluorescente (MCF), em três etapas, para a detecção de BAAR em esfregaços de escarro. MÉTODOS: Nossa amostra consistiu de 260 amostras de escarro coletadas de casos suspeitos de tuberculose pulmonar no Kasturba Hospital, em Manipal, Índia. Os esfregaços foram preparados em triplicata, para cada um dos métodos: MCF, MMC e MCG. As lâminas foram numeradas aleatoriamente a fim de que o examinador fosse cegado quanto à identidade das amostras. RESULTADOS: Das 260 amostras, 16 (6,15 por cento), 15 (5,77 por cento) e 13 (5,00 por cento) foram positivas para BAAR com MCF, MMC e MCG, respectivamente. A sensibilidade de MCG e MMC em relação à de MCF foi de 81,25 por cento e 93,75 por cento, respectivamente. Houve boa concordância de MCG e MMC com MCF (0,988 e 0,996, respectivamente), e não houve diferenças estatísticas significativas. CONCLUSÕES: Embora MCG e MMC apresentaram menor sensibilidade que MCF, que é avaliado por microscopia de fluorescência, consideramos que os dois primeiros métodos sejam promissores no diagnóstico de tuberculose.

OBJECTIVE: In developing countries, sputum smear microscopy is the main tool for pulmonary tuberculosis case finding. The objective of the present study was to evaluate the diagnostic efficacy of Gabbett's staining (GS) and modified cold staining (MCS), both of which are two-step methods, in comparison with that of fluorescent staining (FS), which is a three-step method, for the detection of AFB in sputum smears. METHODS: Our sample comprised 260 sputum samples collected from individuals suspected of having pulmonary tuberculosis at Kasturba Hospital, in Manipal, India. Smears were prepared in triplicate: one each for FS, MCS, and GS. The smears were randomly numbered so that the examiner was blinded to the sample identities. RESULTS: Of the 260 samples, 16 (6.15 percent), 15 (5.77 percent), and 13 (5.00 percent) showed positive AFB results with FS, MCS, and GS, respectively. The sensitivity of GS and MCS, in comparison with that of FS, was 81.25 percent and 93.75 percent, respectively. The concordance of GS and MCS with FS was good (0.988 and 0.996, respectively), and no statistically significant differences were found. CONCLUSIONS: Although MCS and GS were found to be less sensitive than was FS, which is evaluated under fluorescence microscopy, the first two are promising methods for the diagnosis of tuberculosis.